350 chevy transmission diagram

Transmission building involves careful assembly. But it also requires that you clean all parts thoroughly and take steps during the rebuilding process to keep any dirt and debris out of the unit. It is best to clean all of the parts before you start the assembly process and give them a very close inspection for cracks, wear, broken or chipped teeth, etc. Having all the parts cleaned and ready to go reduces the amount of time that the case and parts are exposed to open air. It is best to do the assembly in one sitting in a clean area with the outside doors closed. Minimize traffic in and out of the work area, and use a 55-gallon garbage bag to cover the case when you leave the shop for extended periods of time.

 

---

This Tech Tip is From the Full Book, GM TURBO 350 TRANSMISSIONS: HOW TO REBUILD AND MODIFY. For a comprehensive guide on this entire subject you can visit this link:

LEARN MORE ABOUT THIS BOOK HERE

 

SHARE THIS ARTICLE: Please feel free to share this article on Facebook, in Forums, or with any Clubs you participate in. You can copy and paste this link to share: https://www.chevydiy.com/gm-turbo-350-transmission-installation-guide/

---

 

Before you begin the assembly process, thoroughly clean the transmission case, and bolt it into a suitable holding fixture. Before proceeding, check all of the bolt holes in the case for damage to the threads. Thread repairs are covered in Chapter 2 and need to be done before you begin reassembly. Because thread repair involves drilling and tapping, you create a considerable amount of metal chips that could easily fi nd their way into the assembly. Automatic transmissions rely on hydraulic fluid and pressure to work correctly, so there are multiple passages and moving parts, including valves, that need to move freely for correct function. Any dirt or debris that finds its way inside the unit during assembly is likely to create function issues later on when the transmission is placed in service.

 

 

 

 

Be sure to also check the case very closely for cracks. I’ve seen a few TH350 cases cracked in the bellhousing area. These cracks are usually located where the main part of the case starts to fl air out into the bellhousing area, but may not be visible at a glance. You need to clean the case well enough to locate any cracks prior to assembly. This may involve some extra effort to remove paint or old undercoating that may be covering up troubled areas.

You must also closely inspect the case lugs at the center support. Case repairs and upgrades are covered later in this chapter. Even so, if your case or the case lugs at the center support are heavily worn or damaged, you may want to replace these parts, even if you are upgrading the center support or installing a “case saver” during the rebuild.

Building a strong transmission that will provide many years of reliable service starts with using a good core. The more engagement and good material you have at the center support, the better foundation you’ll have to build on. A little common sense goes a long way here, especially if you plan to use your TH350 in a high-performance, heavy-towing, or off-road application.

 

Case Bushing Removal and Replacement

Step 1:

Once the case is cleaned and securely mounted in the holding fixture, drive out the case bushing. Locate the correct bushing driver for this task if you have one. It removes the bushing without gouging the case.

 

Step 2:

If you don’t have a bushing driver, a long tapered flat-nose punch works fine. Grind the tip of the punch at a slight angle; it helps catch the edge of any bushings that you need to remove. It really helps if you can fi nd the parting line in the bushing and strike it there. They collapse and come out with less effort.

 

Step 3:

The case bushing is driven in from the front. It is also set slightly below flush in the case to allow room for the lip of the output shaft’s Torrington bearing. Apply a small amount of red Loctite to all bushings before driving them in place.

 

Step 4:

Use a long heavy metal rod to drive in the case bushing. Most handles on bushing driver sets are far too short.

 

 

 

Low/Reverse Apply Piston Installation

Step 1:

The low/reverse apply piston is the first item installed once the bushing is in place. Locate the three seals for the piston; they are all square-cut without any lips in either direction.

 

Step 2:

Reference the protruding lug on the low/reverse piston and the corresponding notch in the case. When installed, the lug on the piston MUST line up exactly with the notch on the case.

 

Step 3:

Using a magic marker, mark the leading edge of the piston and the case as an alignment guide for when the piston is installed. Use plenty of clean ATF, or Trans Gel, on the seals. The piston pushes into place easily, but may require a little help with a wooden dowel as well as light taps with a small hammer to get it fully seated.

 

Step 4:

Locate the low/reverse spring cage and snap ring. This unit uses a spring cage with all of the springs attached to it. Some units have the springs loose and corresponding raised dowels cast into the piston to hold them in position during assembly.

Step 5:

Place the low/reverse spring cage and snap ring on the piston. Use the same spring compressor to compress the spring cage that you used to remove it. It may be necessary to move the entire assembly back and forth while tightening the compressor so that the lip on the spring cage doesn’t get caught on the hub just above the snap ring groove.

Step 6:

Install the snap ring and release the spring compressor. Make sure that the ends of the snap ring are between the raised areas of the spring cage.

 

 

Output Shaft Front Bushing Removal and Replacement

Step 1:

Clamp the output shaft in a vise with soft jaws. Remove the bushing inside the front of the output shaft. Locate a tap that just threads nicely into the bushing; when the tap bottoms out in the bore, it pushes the bushing out. Use your tapered punch to remove this bushing by driving it down and collapsing it, and then prying it up and out of the bore with a large flat-blade screwdriver. Be sure to blow out any chips left by the bushing-removal process from the output shaft bore and oil holes.

Step 2:

Locate a suitable driver to push the new bushing into the output shaft. Apply a small amount of Loctite to the bushing.

 

Step 3:

Install the bushing in the output shaft. Note that the top edge of the bushing is seated to the bottom of the counter bore, or below flush. Some bushing kits come with a plastic split bushing that you can use  instead of the metal bushing. The plastic bushing is fi ne; it’s much easier to install and works better than the metal bushing if the hub of the forward clutch that rides in the bushing is not in perfect condition.

 

 

Component Installation

Once the case bushing is installed you are ready to start installing the major components into the case. I address each part individually as I proceed with the assembly. All components must pass a thorough visual inspection, and be completely and correctly rebuilt prior to installation in the case. The basic rules for transmission building apply to all units. Some sort of thrust washer or Torrington bearing is used between any two components that ride together in the assembly and have the potential to turn at different speeds. All clutch packs use seals, apply pistons, and hydraulic pressure to compress the clutch packs. This involves using sealing rings in addition to the holes in shafts and passages in the case to ensure that the pressurized oil makes it to the intended location without losing pressure because of insufficient flow.

 

Output Shaft with Torrington Bearings Installation

Step 1:

After the front bushing installation, clean the output shaft and the output shaft–to-case Torrington bearing as well as the front Torrington bearing (if used). Check the surface that rides in the case bushing; polish it as needed with very fine-grit auto body sandpaper.

 

Step 2:

The front bearing on this transmission is also a Torrington bearing. A metal thrust washer may be used at this location instead. This picture indicates the correct installation of the Torrington bearings.

 

Step 3:

The rear Torrington bearing is installed as shown. Note the lip on the bearing; it requires the output shaft bearing to be seated below flush.

 

Step 4:

The front Torrington bearing is installed as shown. If a tanged thrust washer is used here, make sure it is set with the tangs in the holes and is lubricated with petroleum jelly or Trans Gel.

 

Step 5:

Lubricate all of the mating surfaces with clean transmission fluid and install the output shaft into the case. It should turn freely without binding.

 

 

Low Planetary Bushing Removal and Replacement

Drive the old bushing from the low planetary as shown.

 

Step 2:

Locate a suitable driver to install the low-planetary bushing. It is driven in until flush, so almost any driver slightly wider than the bushing will work.

 

Step 3:

Install the new bushing from above. Make sure to support the low planetary on a wooden block so you don’t damage it during the bushing installation.

 

Step 4:

The bushing has been driven in straight and flush with the bore. A quick test fi t on the output shaft verifies correct bushing installation. It must turn freely without any tight spots.

 

Low Planetary Pinion Inspection

Step 1:

Check the endplay on each pinion as shown. Also spin each pinion and wobble them back and forth. If endplay is beyond .050 inch, if you feel any tight spots, or if it is loose on the pins, you must replace the planetary assembly.

 

Step 2:

Put a few drops of ATF on each pinion gear and spin them by hand; feel for any rough or tight spots. If they don’t pass this test, replace the planetary.

 

Step 3:

Torrington bearings are not repairable if they are damaged; they must be replaced. Even so, they seldom give any trouble. The best method to clean them is to submerge them in clean transmission fluid. Once they are well lubricated, turn them by hand and feel for any roughness or tight spots. Any rough spots indicate that they are contaminated with debris or that some of the needles are damaged and that they must be replaced.

 

Low Planetary Installation

Step 1:

Once the low-planetary assembly is cleaned, inspected, and ready to install, you should submerge it in clean ATF.

 

Step 2:

Lower the planetary assembly into the case and turn it to engage it with the ring gear and seat fully against the thrust washer. Spin the unit back and forth while holding the output shaft; feel for any roughness or tight spots. It should turn freely in both directions.

 

Low/Reverse Clutch Pack Installation

Step 1:

Locate the low/reverse frictions. This unit used five frictions; some lighter-duty units may use only four.

 

 

Step 2:

Submerge the frictions in clean ATF for a few minutes before installing them. Even though many builders do not do this, it ensures that the frictions don’t get a “dry start” when the transmission is first placed in service.

 

Step 3:

Locate the five low/reverse steels. A notch references the location of the steel in the case, even though they only install one way.

 

Step 4:

Starting with a steel, you alternate steel, friction, steel, friction, until all five steels and frictions are installed. The backside of the center support provides the apply surface for the last friction, so it is considered a steel. Note the location of the notch on the steels in the bottom of the case, and that the last friction is very close to the top of the low planetary, although it is still fully engaged.

 

Step 5:

Install the center support and retaining spring next. Note the location of the retaining spring in the case. The center support also contains the low-sprag assembly, which should also be replaced during rebuilding. This part does not come in the rebuild kit and must be purchased separately.

 

Center Support Installation

Step 1:

Install the center support retaining spring as shown. Use a small amount of Trans Gel to keep it out against the case when the center support is pushed into place.

 

Step 2:

Install the center support and push it fully into place as shown. Notice how the retaining spring also loads the center support against the case lugs, and how much clearance is present.

 

Step 3:

Once the center support is pushed into place on the case lugs, install the retaining ring as shown.

 

Step 4:

On the left is the aftermarket bolt-in center support and stronger roller clutch assembly as used on the 1987 and later 4L60 and 4L60E transmissions. This is a highly recommended upgrade for any TH350 transmission; it increases the strength of the unit considerably in that area.

Step 5:

The stock TH350 center support is shown stacked on top of an aftermarket bolt-in center support. Note how much longer the rollers are on the aftermarket part.

 

Step 6:

Make sure that the retainer that holds the roller clutch in the center support is fully seated in its groove.

 

 

Center Support Assembly Bolt Installation

Step 1:

Install the new center support and retaining ring in the same manner that you would install a stock center support. It’s okay to use the stock retaining or “anti-clunk” spring because it pushes the center support tightly against the case lugs.

 

Step 2:

Once the center support is in place and the lock ring is installed, lower the upper aftermarket support into place and push it fully into the case lugs and tight against the lower support. It may have a very tight fit in the case lugs.

 

Step 3:

Install all eight hardened screws. Be sure to use some red Loctite on them.

 

 

 

Inner Race and Thrust Washer Installation

Step 1:

Locate the inner race for the low/reverse roller clutch.

 

Step 2:

Install the inner race for the low-roller clutch. Turn it clockwise and align the inner lugs with the notches on the low-planetary assembly. It pushes into place easily once lined up correctly.

 

Step 3:

Locate the new thrust washer for the sun shell. The stock thrust washer was probably plastic; the replacement should be metal.

 

Step 4:

Install the sun shell thrust washer onto the inner roller clutch race. Be sure to lubricate both sides with a small amount of Trans Gel or ATF.

 

Sun Gear Bushings Removal and Installation

Step 1:

Use a sharp punch to drive out the upper bushing inside the sun gear. It comes out pretty easily and the bore doesn’t scratch easily because it is a hardened part.

 

Step 2:

Flip the sun shell over and drive out the lower bushing. Rest the gear on a block of wood or shop towel to help you avoid damaging it.

 

Step 3:

Locate and drive in the upper bushing with a suitable driver. It should be flush with the inner fl at edge of the counterbore in the sun gear. Make sure to use some red Loctite on the bushing.

 

Step 4:

Install the lower bushing next. Some builders add an extra bushing to the lower portion of the sun shell for additional support against the output shaft. If you choose to do this, make sure to check the oil lubrication holes; drill them if necessary.

 

 

Sun Shell Installation into Case

Step 1:

Lubricate the sun shell with clean ATF. Get plenty of lubricant on the inner bushings and on the lower area that comes in contact with the thrust washer.

 

Step 2:

Install the sun shell and gear into the case. Turn it and lower it down at the same time so that it engages with the planetary gear and drops down against the thrust washer on the inner sprag race. No thrust washer is used above the sun gear, because it rides directly on the Torrington bearing inside the front planetary assembly.

 

Front Planetary Installation

Step 1:

Submerge the front planetary assembly in fresh ATF. Inspect the pinions for damage and endplay, as you did with the low-planetary assembly.

 

Step 2:

Install the planetary assembly onto the sun gear. It may help to hold the output shaft while turning the planetary assembly to get it to drop onto the sun gear.

 

Step 3:

Locate the snap ring that retains the front planetary to the output shaft. Set it on the end of the output shaft.

 

 

Step 4:

Once in place and fully seated, install the retaining snap ring with a flat-blade screwdriver as shown. It helps to push one side down and then walk it around the end of the shaft while pushing it down into the retaining groove.

 

Step 5:

Clean the front planetary Torrington bearing with clean ATF. Turn it and feel for rough spots, which are tight when it turns. This indicates that it has debris inside or is damaged. Damaged or dirty Torrington bearings are not serviceable and must be replaced.

 

Step 6:

Install the Torrington bearing on the front planetary. Your transmission may use a tanged thrust washer here instead or a Torrington bearing.

 

Step 7:

Note that there are two types of carriers. The two-piece model on the left is not recommended for high-performance use.

 

 

 

Front Planetary Reaction Carrier Bushing Installation

Step 1:

Use a sharp punch to remove the bushing inside the front planetary carrier.

 

Step 2:

Apply a small amount of red Loctite to the new bushing and drive it into place.

 

Step 3:

Because it stops flush with the upper surface, almost any fl at bushing driver that is wider than the diameter of the bushing can be used to install it. Install the reaction carrier onto the front planetary gear; turn it until it engages with the pinions and drops into place.

 

Step 4:

Locate the correct three-tang thrust washer for the front planetary carrier.

 

Step 5:

Put some Trans Gel on the backside of the thrust washer and install it on the carrier. The grease helps it stay in place when you install the forward clutch assembly.

 

 

 

Forward Clutch Drum Rebuild

Rebuilding the forward clutch is a relatively easy process. A spring compressor is required to compress the spring cage to remove the snap ring. Because the input shaft is attached to the forward drum, it should be left in place during the rebuilding process. This requires that the spring compressor must have the ability to accommodate the input shaft and still compress the spring cage.

 

Forward Clutch Disassembly

Step 1:

You are now ready to rebuild and install the forward clutch assembly. The input shaft is attached to the drum.

 

Step 2:

Note the small shaft on the underside of the forward clutch. It engages with the bushing in the front of the output shaft. Polish this surface with fi ne auto body sandpaper. Replace the entire assembly if it is badly worn or damaged.

 

 

Step 3:

Remove the large snap ring as well as the frictions and steels. Keep them in their original configuration for the clutch count. Some light-duty TH350s use four frictions in this drum; most units have five. The first steel should be “waved,” but it is common for builders to use flat steel at this location.

 

Step 4:

Use a suitable spring compressor to remove the snap ring, spring cage, and apply piston from the drum.

 

Step 5:

Clean all of the components and lay them out on a clean pan or shop towels.

 

Forward Clutch Apply Piston Installation

Step 1:

Locate and install the new lip seals for the forward apply piston. The lips on both seals go down toward the drum.

 

Step 2:

Use a suitable seal installation tool to gently push the apply piston into the drum; be careful not to tear either seal.

 

Step 3:

The drum should turn freely once in place.

 

 

Step 4:

Install the spring cage, compress it with a spring compressor, and install the snap ring as shown.

 

 

Step 5:

The ends of the snap ring should be located between two of the raised areas on the retainer.

 

 

 

Forward Clutch Pack Installation

Step 1:

Install the forward clutch pack steels and frictions. Note that you start out with a waved apply steel.

 

Step 2:

Install a fl at steel, friction, steel, and continue until you end up with a friction under the thick backing plate. Install the snap ring and push it out tightly into the groove. Soak the frictions in ATF for at least 15 minutes prior to installation.

 

 

Step 3:

Check for clutch pack clearance. Because the forward clutch is applied for all forward gears, it only needs some clearance to work correctly. The frictions inside the drum should turn freely once the snap ring is in place. Factory clearance is .020 to .040 inch, but it will be fi ne if it’s a little tighter. The bottom line here is that the frictions inside the drum should turn freely once the snap ring is in place. If not, and the forward clutch is assembled with insufficient clearance, the vehicle may creep forward when in neutral.

 

 

Step 4:

Install the forward drum in the case. (Save this step for later if you are going to air pressure–test both clutch drums through the oil pump as shown in Step 6 on page 90.)

 

Step 5:

During assembly, turn the input shaft until all five frictions are fully engaged with the front planetary carrier. Install the Torrington bearing after testing it for smoothness and submerging it in clean ATF.

 

 

Step 6:

Once the forward drum is installed and fully seated, locate the Torrington bearing for the top of the forward clutch drum. Clean, inspect, and submerge it in clean ATF prior to installation.

 

Step 7:

Install the Torrington bearing on the forward clutch drum as shown. You are now ready for the direct drum.

 

Direct Drum Rebuild

The direct drum is located  behind the oil pump assembly. The intermediate roller clutch, or sprag assembly is attached to the front of the drum, and engaged with the intermediate friction plates in the forward part of the case. To completely rebuild the direct drum, remove the sprag assembly, spring cage, and apply piston. Clean and inspect all components, and install new parts where applicable.

 

Intermediate Roller Clutch Assembly Removal

Step 1:

Remove the large snap ring above the backing plate on the direct drum. Remove the backing plate, frictions, and steel plates.

 

Step 2:

Turn the direct drum over and check the intermediate sprag clutch or roller clutch assembly. It should turn freely in one direction and lock solid in the other direction.

 

Step 3:

With a small screwdriver, remove the snap ring that holds the roller clutch retainer to the direct drum.

 

Step 4:

With the snap ring out of the way, the retaining plate lifts right off, exposing the roller clutch assembly.

 

Step 5:

Remove the roller clutch outer race. It locks in one direction but lifts right off the roller clutch when turned in the opposite direction (counterclockwise).

 

Step 6:

Remove the roller clutch from the drum. Once they’re off the drum, the rollers fall out of the assembly easily. Inspect the inner and outer race, rollers, and springs for damage. Install a new roller clutch assembly with any level of rebuild; the springs tend to crack, break, and lose their tension in high-mileage units.

 

 

Direct Clutch Apply Piston Removal

Step 1:

Using a suitable spring compressor, compress the spring cage for the direct clutch apply piston. Using snap ring pliers, remove the snap ring.

 

Step 2:

Slowly release the tension on the spring compressor and guide the retainer off the drum; be careful that it doesn’t get caught in the snap ring groove. It lifts off the drum easily once it is past the snap ring groove and the tension is removed.

 

Step 3:

In most cases, the apply piston lifts out of the drum easily. If the seals are hardened from many years of use you may have to invert the drum and gently drop it a few inches onto a fl at wooden surface to dislodge the apply piston. Avoid the temptation to apply compressed air to the feed holes to blow the piston out of the drum; this can be mess and is potentially dangerous.

Step 4:

Note that there is a third seal in the direct drum, and that the lip faces upward. Install the new seal with the lip in the same direction.

 

 

Step 5:

Clean all of the components of the direct drum. Inspect the inner and outer race surfaces closely. Most TH350s use four friction plates and four flat-steel plates. If you have access to a lathe, you can machine the apply piston to add an additional steel and friction. Inspect the bushing for wear.

 

 

Direct Clutch Apply Piston Installation

Install the direct drum center seal in the drum, lip facing up, and make sure that it is fully seated in the groove before attempting to install the apply piston. Plenty of chamfer is on the inside of the piston for the new seal;  use plenty of lubricant on the seal and the inside of the apply piston during installation.

 

Step 2:

Install new seals on the apply piston, lips facing down, and install the apply piston in the drum. Use plenty of clean ATF or Trans Gel as a lubricant. Also use a feeler gauge or special seal installation tool (a smooth piece of wire crimped in a piece of copper or soft steel tubing). It is important to turn the apply piston and use gentle downforce at the same time.

Step 3:

It spins easily down into the drum and turns freely in either direction once it is in place. Be careful not to cut, tear, or fold over the lip seals.

 

Step 4:

Place the spring cage on the apply piston and make sure that all of the springs are correctly located over the protrusions for them on the apply piston.

 

Step 5:

Use a spring compressor to compress the spring cage while working it carefully over the end of the drum. Install the snap ring to retain the spring cage, and make sure that the opening in the snap ring does not line up with the raised areas of the cage. Remove the spring compressor.

 

Step 6:

Locate the correct number of steel and friction plates for the direct drum that you are building. Soak the frictions in clean ATF for at least fifteen minutes. Start with a fl at steel plate.

 

Step 7:

Install a friction plate on the first steel plate, then alternate steel, clutch, steel, clutch, to end up with a friction plate.

 

Step 8:

Install the backing plate over the last friction. Make sure that it is fully seated against the last friction. Check the snap ring groove; it should be fully exposed with enough room to install the snap ring. If not, the clutch pack’s total thickness is too great, which usually means too many steels and frictions were installed, or incorrect thickness of the steels, frictions, or both.

 

Step 9:

Install the snap ring for the backing plate. Check the clutch pack clearance. It should be .040 to .060 inch. Minimum clearance is .030. More than .060 may result in a slight delay on engagement.

 

Step 10:

Note that I am installing a wider bushing into the direct drum. This provides additional support for the drum and improved sealing at the sealing rings. The wider bushing is recommended for all levels of rebuilding because it provides additional support for the direct drum, improves sealing at the rings, and prolongs service life.

 

 

Direct Drum Bushing Installation

Step 1:

Drive the bushing out as shown with a long tapered punch.

 

Step 2:

Use a wide flat bushing driver to drive the new bushing in flush with the bearing surface as shown. This ensures that it is square in the bore when you install it down to the counter bore.

;

Step 3:

Install the new bushing to the depth as shown in the pictures. Since this bushing is driven in below flush, use a suitable driver to keep it straight and not damage the inner surface during the procedure.

 

 

Intermediate Roller Clutch Assembly Installation

Step 1:

Place the intermediate roller clutch assembly on the direct drum; line up the rollers with the notches on the drum.

 

Step 2:

Carefully push the roller clutch assembly onto the drum. You may have to push each roller in slightly to get it started. Be careful not to dislodge any of the rollers during this process.

 

Step 3:

Install the intermediate clutch outer race. Turn the outer race counterclockwise while applying downward pressure at the same time. It easily rolls into position and seats against the drum.

 

Step 4:

Install the roller clutch retainer. Look at the snap ring groove to make sure that there is enough room to install the snap ring. If not, the roller clutch or outer race is not fully seated.

 

Step 5:

Install the snap ring over the retainer. The snap ring ends should be between the notches in the drum as shown. Be sure that the snap ring is fully seated. Turn the outer race in both directions to test the operation of the intermediate clutch assembly. It should turn freely counterclockwise, then lock solid when turned clockwise.

 

 

Step 6:

Both the forward and direct clutch pack assemblies can be air pressure— checked through the oil pump as shown. Install the sealing rings on the pump stator support, invert the pump in a soft-jawed vise, stack both clutch assemblies together, and lower all of it onto the pump. Apply compressed air through the oil supply passages and listen for the clutch apply as well as air leaks.

 

Step 7:

Carefully lower the direct clutch assembly into the case.

 

Step 8:

Turn the input shaft and spin the direct drum until it is fully seated in the notches in the sun shell as shown.

 

Intermediate Band Installation

Step 1:

Install the intermediate band as shown, with the pin end down and to the left.

 

Step 2:

Slip the band over the direct drum and align it with the notch in the case.

 

Step 3:

Be sure that the band is fully engaged in the notch as shown.

 

Oil Pump Assembly Rebuild

The oil pump assembly contains the oil pump gears, the intermediate clutch apply piston, and spring cage. The hub end also has the sealing rings for the direct and forward clutch assemblies. Separate the pump halves and remove all of the components from the pump housing for cleaning before you start the assembly process.

 

Sealing Rings and Thrust Washer Removal

Step 1:

Unhook the ends on all four sealing rings. Some later units may use scarf-cut Tefl on rings instead of metal rings with hooked ends.

 

Step 2:

Remove the four sealing rings from the grooves in the pump support.

 

Step 3:

Remove the thrust washer and any shims under it. A Torrington bearing is used on later units as shown. Most early units use a tanged thrust bearing here. During removal, take note of any shims under the bearing or the thrust washer.

 

Oil Pump Disassembly

Step 1:

Loosen and remove the five pump bolts. A 3/8-inch impact works well here, because holding the oil pump while trying to loosen the bolts with a ratchet and socket at the same time can be difficult.

 

Step 2:

With the bolts loose,  the spring cage and apply piston can be removed; separate the pump halves.

 

Step 3:

Lift the intermediate apply piston out of the oil pump housing. Note that both the inner and outer lip seals face down toward the pump.

 

Step 4:

Clean all of the pump parts and place them on a clean surface.

 

Pump Seal and Torque Converter Bushing Removal

Step 1:

Use a sharp tapered punch to remove the front seal.

 

Step 2:

Support the oil pump’s front half on two wooden blocks. Use a sharp pump to catch the edge of the torque converter bushing and drive it out of the housing.

 

Pump Stator Bushing Depth Measurement and Orientation

Step 1:

Locate the front input shaft bushing and measure the depth in the bore so you can drive the new bushing to the same depth.

 

Step 2:

Repeat this procedure for the two lower bushings.

 

Stator Bushings Removal

Step 1:

Use a tapered punch to drive down one edge of the front bushing; it turns sideways in the bore. Repeat this procedure for both lower bushings.

 

Step 2:

Remove the two lower bushings in the same manner as the front bushing.

 

 

Step 3:

The lower bushings turn sideways in the bore. Pry them out as shown.

 

 

 

 

Stator Bushings Installation

Step 1:

Drive two new bushings into the lower end of the stator. Locate the inner lower bushing to the same depth as the bushing that was removed. It should be just below the oil supply hole, not blocking it.

 

Step 2:

Drive in a new front bushing. A suitable driver that is slightly smaller than the bore is required because the bushing must be below flush.

 

 

Step 3:

Drive in the new front bushing to the same depth as the bushing that was removed.

 

Step 4:

It is a good idea to test fit the pump assembly by sliding it down over an input shaft. If you do not have a spare shaft, you can use the forward clutch assembly for this purpose. Input shaft bushing installation can be difficult with the transmission. The new bushings may be tight on the input shaft; you may have to sand any tight spots gently with fine auto body sandpaper.

 

Torque Converter Bushing Installation

Always install a new torque converter bushing for any level of rebuild. Doing so ensures correct alignment of the torque converter drive hub in the oil pump inner gear, which reduces side loading and improves front seal life.

 

Torque Convertor Bushing and Seal Installation

Step 1:

Drive in a new torque converter bushing. Any driver slightly larger than the bushing and smaller than the bore in the housing works fi ne. The bushing is driven in flush.

 

Step 2:

Drive in a new front seal. Because it drives in flush with the outer edge of the pump casting, almost any driver that is wider than the seal will work.

 

 

Step 3:

Note that a spring is inside the seal lip. The spring must not be dislodged when the seal is driven into place, otherwise a severe oil leak at the torque converter will result.

 

Step 4:

Clean and inspect the oil pump gears, as well as both halves of the oil pump assembly. Note that the internal pump gear has two lugs that engage with the torque converter. These lugs must be installed toward the rear of the transmission, or farthest away from the torque converter hub. Failure to do so results in pump breakage and transmission failure.

 

Step 5:

Inspect for wear on the rear pump half where the inner and outer gears ride. Minor scratches are okay, but deep grooves here are not acceptable. Very minor scratches can be buffed or sanded out with fine auto body sandpaper.

 

Step 6:

Lubricate the oil pump and gears prior to assembly. Use only clean ATF here; do not use petroleum jelly or Trans Gel.

 

Step 7:

Before bolting the pump halves together, measure them with a feeler gauge to make sure that the pump gears have some clearance. This should not be a problem unless a service replacement set of gears are used, or gears were taken from another oil pump.

 

Intermediate Clutch Apply Piston Installation

Step 1:

Place two new seals on the intermediate apply piston, lips facing down. Apply a generous amount of ATF or Trans Gel to the seals and inside the pump housing. Use a lip seal tool to install the apply piston into the housing; make sure it is fully seated and turns freely.

 

Step 2:

Install the spring cage over the apply piston. Install the pump bolts through the spring cage and gently pull the pump halves together by tightening the bolts finger tight.

 

Step 3:

Install the oil pump band and tighten with a large flat-blade screwdriver.

 

Step 4:

Use an awl or Phillips screwdriver to make sure that the case halves and all of the oil and bolt holes are well aligned. Clamp the halves with a band clamp and tighten the bolts finger tight.

 

 

Step 5:

Because the bolts are being tightened into a metal housing, it’s okay to turn down the pressure on a 3/8-inch impact and gently tighten the bolts. This effectively holds the pump halves together until the unit is held stationary for final torque to 15 ft-lbs. Remove the metal clamp after the final torque.

 

Intermediate Clutch Pack Installation

Step 1:

Install the intermediate clutch pack into the case. Start with the thick factory backing plate.

 

 

Step 2:

Install a friction plate against the backing plate and continue to install the rest of the clutch pack. Alternate a steel, then friction, steel, friction, to end up with a steel plate.

 

Step 3:

Note that all of the steels for the intermediate clutch pack have a notch as shown, which is installed in the lower right of the case.

 

 

Step 4:

Place the waved apply spacer on top of the apply plate. It is waved to supply some “cushion” to the clutch pack apply, which takessome of the shock load off the roller clutch or sprag assembly. Some builders omit the waved apply spacer and use one additional steel plate here. This shortens the 1-2 shift and makes it firmer. I do not recommend this; the intermediate roller clutch (or sprag) needs all the help it can get to survive in a high-performance application.

 

Step 5:

The intermediate clutch pack is now installed. Note the depth of the last friction on the outer race. You ended with a waved apply spacer that has one flat steel under it.

 

 

Thrust Washer and Sealing Rings Installation

Step 1:

Install any shims that were removed from under the pump thrust washer. Install it as shown, with the housing facing up or toward the rear of the transmission. Use the factory shims for the first trial assembly. Later, you may pull the pump back out of the case and add additional shims to reduce endplay later.

Step 2:

Install the Torrington thrust bearing over the factory shim. Be sure to install it as shown, with the housing facing up or toward the rear of the transmission.

 

Step 3:

Early units used a thrust washer at this location. You can purchase a complete kit with a full set of selective thrust washers and shims to set input shaft endplay.

 

Step 4:

Install the pump sealing rings. Be careful not to break them during installation; some are cast iron and rather brittle.

 

Step 5:

Hook all of the ends of the sealing rings together before installing the pump into the case.

 

Step 6:

Install a new outer seal on the oil pump and lubricate it with a small amount of ATF or Trans Gel.

 

Step 7:

Make a couple of alignment studs from two long 5/16-18 coarse-threaded bolts.

 

Step 8:

Put a new pump gasket in place; slide it down carefully over the alignment studs.

 

Step 9:

Lower the pump assembly carefully onto the alignment studs. Lubricate the outer rubber seal and sealing rings with clean ATF.

 

Step 10:

Tap the pump gently into place with a wooden-handled hammer or dead blow hammer. Do not force the pump into the case. If it does not seat easily and flush, remove the pump and check the hooked sealing rings, and check that both clutch drums are fully seated in the case.

 

Step 11:

Install new sealing washers on the pump bolts. They provide a back-up seal in case any transmission fluid tries to migrate up the bolt holes from inside the unit.

 

Step 12:

Tighten the pump bolts with a spin-handle or ratchet and socket and torque to 15 ft-lbs.

 

Step 13:

Once the pump is tightened, check the input shaftendplay. Use a small awl or screwdriver to pry upward on the input shaft as shown. Shaft endplay should be .015 to .030; use selective shims under the Torrington bearing or selective washers and shims to correct the pump endplay to within specifications.

 

 

Speedometer Installation

Carefully inspect the speedometer drive gear for wear and cracks. It is somewhat difficult to access after the transmission is installed in the vehicle, so you want to replace it during rebuilding if it shows wear or damage.

 

 

Speedometer Drive Gear Installation

Step 1:

Place the speedometer drive gear retainer on the output shaft. Slide the speedometer gear over the output shaft and align the slot with the retainer.

 

Step 2:

Slide the speedometer gear over the retainer. It may have a tight fit on the shaft and require a light coaxing with a machinist hammer or screwdriver to secure it in place.

 

Step 3:

Make sure that the retainer snaps over the end of the gear as shown.

 

Tail Housing Seal and Bushing Replacement

Step 1:

Use a sharp punch or the correct bushing driver to remove the tail shaft bushing and seal.

 

Step 2:

Install the new bushing with a suitable driver.

 

Step 3:

Drive the new bushing flush with the inner bore of the housing as shown.

 

Step 4:

Drive a new seal into place. Almost any driver larger than the seal works for this purpose.

 

Step 5:

Drive the seal down until the lip sits flush on the housing; check that the seal spring did not come off the seal during the installation process.

 

Step 6:

Install the case to tail housing seal as shown.

 

Step 7:

Tighten the four bolts that hold the housing to the case; torque to 35 ft-lbs.

 

Speedometer Housing Rebuild and Installation

Step 1:

Locate all of the parts for the speedometer housing. Remove the O-ring on the housing as well as inner seal and retaining ring.

 

Step 2:

Install the O-ring on the housing.

 

 

Step 3:

Install the inner seal with the lip facing toward the gear.

 

 

Step 4:

Install the inner seal retaining ring.

 

Step 5:

Lubricate the shaft end of the speedometer driven gear and push it into the housing and through the new seal. Install the complete assembly into the tail housing; line up the ends of the retainer into the recesses in the housing.

 

Step 6:

Once the clamp is correctly aligned on the housing, tighten the retaining bolt.

 

 

Governor Installation

Step 1:

Locate the governor, governor housing, and retainer. Inspect the governor gear closely for wear or damage. Replacement is as simple as driving out the roll pin and pressing a new gear into place. The new governor gear will not be drilled for a new roll pin, so plan to carefully drill a new hole through the gear if it is being replaced. Check the governor weights and springs, and see that the plunger moves freely. There is usually no need to take the governor apart for cleaning or to replace the gear; just be sure that it is not damaged and all of its parts move freely.

Step 2:

Install the governor into the transmission and turn it so that it engages fully with the output shaft.

 

Step 3:

Install a new seal on the governor cover.

 

Step 4:

Gently drive the governor cover in place. It can be started and squared up with a few taps from a soft-faced mallet.

 

Step 5:

Finish driving the governor cover into place with a flat-faced punch. Check that the governor cover is fully seated.

 

Step 6:

Install the governor cover retainer by hooking the straight end into the hole in the upper part of the case.

 

Step 7:

Snap the bent end of the retainer firmly into the notch in the lower part of the case.

 

 

Accumulator Seals Removal and Replacement

Step 1:

Locate the 1-2 accumulator and its components.

 

 

Step 2:

Many accumulators have solid Teflon seals on them. Cut the seals with a sharp pocketknife, scribe, or awl to remove them.

 

Step 3:

Most rebuild kits come with the hook-end metal sealing rings shown. Replace the lower seal with a metal ring and hook the ends together.

 

Step 4:

Replace the upper ring in the same manner as the lower ring.

 

Step 5:

Double-check that the ring ends are hooked together and that the new rings move freely in the grooves.

 

 

1-2 Accumulator Installation

Step 1:

Lubricate the case bores and the 1-2 accumulator seals with clean ATF. Install the 1-2 accumulator into the case.

 

Step 2:

Install the 1-2 accumulator spring.

 

Step 3:

Install the accumulator cover with a new seal on it. Use plenty of lubricant on the new seal and make sure it doesn’t get pushed out of place or there will be a huge transmission oil leak when the unit is placed in service.

 

Step 4:

Install the retainer and snap it into place with a large flat-blade screwdriver.

 

Step 5:

Use a suitable driver to install the manual shaft seal into the case. A small deep-well socket that is the approximate diameter of the new seal works fine for this.

 

Intermediate Servo Installation

Step 1:

Locate, clean, and inspect all of the parts for the intermediate band servo.

 

Step 2:

Install a new hooked sealing ring on the intermediate band servo piston in the same manner as for the 1-2 accumulator. Install the washer and pin as shown.

 

Step 3:

Next, install the return spring and retainer as shown.

 

Step 4:

Place the return spring and retainer into the bore in the case. Lubricate the sealing ring and pump bore with clean ATF. Do not force the piston into the bore or you may break the sealing ring. It should push into place with gentle hand pressure.

 

Step 5:

Push the band apply servo to the bottom of the bore and observe the band apply through the hole in the case as shown.

 

Manual Shaft Installation

Step 1:

Locate and clean the parts for the manual shaft installation.

 

Step 2:

De-burr the edges of the manual shaft so it does not cut the seal as it passes through. Install the manual shaft through the case and case seal.

 

Step 3:

Install the “rooster comb” and retaining nut.

 

Step 4:

Tighten the retaining nut. Torque specification is 20 ft-lbs.

 

Step 5:

Locate the spacer for the manual shaft.

 

Step 6:

Push down firmly on the spring spacer until it snaps onto the manual shaft.

 

Step 7:

Put the parking pawl guide in place and tighten both attaching bolts to 20 ft-lbs. Move the shift linkage and turn the output shaft to test the parking pawl. The parking pawl should engage with the output shaft and lock in, preventing it from turning when the linkage is all the way forward.

 

 

Step 8:

Install the oil pump pressure screen/filter into the case.

 

Step 9:

Install the governor filter into the case.

 

Vacuum Modulator Installation

Step 1:

Locate the modulator valve, new modulator, and seal.

 

Step 2:

Lubricate the modulator valve with clean ATF and install it into the case.

 

Step 3:

Place a new seal on the modulator and install it into the case.

 

Step 4:

Install the clamp for the modulator and tighten the bolt to 12 ft-lbs.

 

Step 5:

Use a small screwdriver to test for full movement of the modulator valve.

 

 

Valve Body Installation

The TH350 valve body is cast iron and has steel valves. It is a durable part and seldom gives any troubles. You do not have to take it apart except where noted below. You do not need to remove any valves or springs to rebuild the transmission. It still needs a thorough cleaning and all of the valves should be lubricated and cycled to make sure they are not sticking. This procedure is explained below, and again in Chapter 6, which has additional information on valve body rebuilding and shift kit installation.

 

Separator Plate Installation

Step 1:

Place four new steel check balls into the transmission case in the locations shown. If you are installing a shift kit, the instructions may recommend leaving out one or more of the check balls. Follow the shift kit’s directions exactly.

 

Step 2:

Install the lower valve body gasket. If you are performing a stock rebuild, always use the stock gaskets. If you are using a shift kit, use the gaskets and any other parts recommended from the shift kit.

 

 

Step 3:

Install the separator plate and upper gasket. My rebuild included a TransGo shift kit that uses one additional gasket under the stock support plate as shown.

 

Step 4:

Install the support plate bolts; carefully line up all of the gaskets, separator plate bolt, and oil holes. Tighten the support plate bolts to 10 ft-lbs.

 

Step 5:

Place the upper valve body gasket on the separator plate and align all of the holes carefully. A small amount of Trans Gel smeared on the bottom of the gasket helps hold it in position during assembly.

 

Accumulator Removal and Replacement

Step 1:

Using large channel lock pliers, or another suitable compressor, compress the 2-3 accumulator and remove the retaining clip.

 

Step 2:

Remove the 2-3 accumulator and spring from the valve body. A good amount of old transmission fl uid may be trapped under the accumulator.

 

Step 3:

Clean the 2-3 accumulator, spring; remove the old seal. Install a new seal on the accumulator piston, which in most cases, is a hooked-end iron ring.

 

Step 4:

Install the spring, piston, and retaining clip carefully. Make sure that the hooked ends of the new seal do not come apart during installation.

 

Step 5:

Compress the 2-3 accumulator piston and install the retaining clip.

 

Step 6:

Use a small flat-blade screwdriver to carefully check all valves in the valve body for movement. They should move freely without sticking or binding. Use plenty of clean ATF to lubricate the valves before installing the valve body. The installation of an aftermarket shift kit usually requires that some of the valves be removed and the springs be replaced.

Step 7:

Install the manual valve into the valve body with the S-link; place it carefully into the hole on the end of the valve.

 

Step 8:

Lower the valve body onto the case. At the same time, engage the S-link with the linkage.

 

Step 9:

Install all of the valve body bolts by hand and be careful that none of them are cross-threaded. Tighten a couple of the bolts gently to keep the valve body in position.

 

Step 10:

The bolt holding down the leaf spring for the rooster comb may be difficult to start in the case. Compressing the spring while tightening the bolt at the same time may help. Gently tighten the remaining valve body bolts, then torque to final specifications.

 

 

 

Step 11:

Locate and install a new filter and gasket. At least three different styles of filters are available for the TH350 transmission. The micro screen–type filters are recommended for their high-flow capabilities.

 

Step 12:

The filter is clearly marked “front” for correct installation.

 

Step 13:

Install the two 1/4-20 bolts or screws that attach the filter to the valve body. Replacing the factory slotted screws with Grade-5 or Grade-8 hex-head bolts makes them easier to tighten to specifications.

 

Step 14:

Install the kick-down linkage, rod, and clip, if they are being used.

 

 

Step 15:

Install the oil pan gasket to the case. The fiber gasket is preferred over rubber or cork gaskets. They will not leak if the oil pan is fl at and in good shape. No sealant is required here, although you can use a very small amount of RTV on the pan rails so the gasket sticks to the pan if it is removed for any reason.

Step 16:

Install the oil pan and pan bolts; tighten to specifications.

 

 

Written by Cliff Ruggles and Posted with Permission of CarTechBooks

Chevy Turbo 350 Transmission Diagram Whats New

Chevy turbo 350 transmission diagram - . . . . . . .

Chevy turbo 350 transmission diagram -

Chevy turbo 350 transmission diagram -

Wiring diagram is a technique of describing the configuration of electrical equipment installation, eg electrical installation equipment in the substation on CB, from panel to box CB that covers telecontrol & telesignaling aspect, telemetering, all aspects that require wiring diagram, used to locate interference, New auxillary, etc.chevy turbo 350 transmission diagram This schematic diagram serves to provide an understanding of the functions and workings of an installation in detail, describing the equipment / installation parts (in symbol form) and the connections.chevy turbo 350 transmission diagram This circuit diagram shows the overall functioning of a circuit. All of its essential components and connections are illustrated by graphic symbols arranged to describe operations as clearly as possible but without regard to the physical form of the various items, components or connections.

Chevy 350 Transmission Diagram Whats New

Chevy 350 transmission diagram - . . . . . . .

Chevy 350 transmission diagram -

Chevy 350 transmission diagram -

Wiring diagram is a technique of describing the configuration of electrical equipment installation, eg electrical installation equipment in the substation on CB, from panel to box CB that covers telecontrol & telesignaling aspect, telemetering, all aspects that require wiring diagram, used to locate interference, New auxillary, etc.chevy 350 transmission diagram This schematic diagram serves to provide an understanding of the functions and workings of an installation in detail, describing the equipment / installation parts (in symbol form) and the connections.chevy 350 transmission diagram This circuit diagram shows the overall functioning of a circuit. All of its essential components and connections are illustrated by graphic symbols arranged to describe operations as clearly as possible but without regard to the physical form of the various items, components or connections.