4L60E Repair Guide - Assembly  

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Inspect all gears, pinions, and carriers for signs of wear, galling, or other damage.  Replace parts as necessary.  Closely inspect the splines in all locations, specifically the reaction sun shell hub and mating reaction sun gear spline, the reaction carrier hub spline, input sun gear, and the 1-2 planetary ring gear carrier hub.  Any signs of damage or cracking in the carriers should indicate a need for replacement. 

Inspect the low-reverse clutch steels and clutch discs.  Any signs of heavy scuffing or burning should indicate replacement.  If the steels are intact, they can be cleaned and lightly honed, stoned flat, or ground to break any surface glazing.  Inspect the reverse clutch spring pack and springs for damage, distortion, or breakage.  Replace any parts as necessary.  Any clutch plates installed new or after solvent cleaning must be soaked in clean transmission oil before assembly.

Assemble the low-reverse support plate and clutch stack on a flat surface and check the overall thickness of the stack at its extreme outer edge.  If the dimension is below 1.200", the steels and/or clutch plates should be replaced. If the dimension is between 1.200" and 1.240", it is acceptable.  Install the clutches into the case.

Test the reverse sprag clutch operation.  It should rotate with some amount of light resistance in the clockwise direction, and not rotate in the counterclockwise direction at all.

Assemble rear input planetary set, sprag clutch, support plate, and large lock ring in reverse order of disassembly. 
Reaction Shell Thrust Washer

Install the reaction sun gear and transmission output shaft.  Install the yellow lock ring onto the shaft to retain the reaction sun gear.

Install the appropriate thrust washer onto the low-reverse sprag hub and retain it with TransGel.  Lightly lubricate the reaction sun gear spline, then align and install the reaction sun shell.  Install the thrust washer inside the shell and retain it with a coating of TransGel. 

Input Planetary Installed

Lightly lubricate and install the input planetary gear set assembly.

The entire reaction power path assembly is depicted here for reference, but refer to the transmission repair manual for specific instructions and details for each section.

4L60E Output Diagram
(Click for larger image)

Disassemble the input drive shell forward clutch, reverse clutch, sprag, direct clutch and inspect all parts.   InputDrumClutches

Remove the lock ring from the 3-4 clutch backing plate, then the backing plate.  Remove the 3-4 clutch steels and plates, apply plate, and retainer, being careful to maintain their order as removed. Inspect the steels and clutch plates as described above, and replace any parts as necessary.

Remove the lock ring for the forward (direct) clutch, then the backing plate.  Remove the forward  clutch steels and plates, the Belleville or waved plate, and the apply plate, and retainer, being careful to maintain their order as removed. Inspect the steels and clutch plates as described above, and replace any parts as necessary.

Remove the forward sprag clutch as an assembly.  Mark the orientation so you know which direction is facing forward on reassembly.

Remove the overrunning clutch plates and steels.  Inspect the steels and clutch plates as described above, and replace any parts as necessary.

Compress the overrunning clutch hub against the spring and remove the shaft lock ring at the hub.  Relax the compression and remove the overrunning clutch apply and forward clutch apply pistons. Lift out the forward clutch housing and spring package, and inspect the springs for damage, distortion, or breakage.  Replace any parts as necessary. 

Inspect the interior of the input drum (torque drive drum) for indications of the clutch steels wearing into the drum guides.  Any grooves can cause clutch steels to stick and interfere with proper clutch engagement or release. 

Replace seals and wipers as necessary before assembly.  With all parts intact, reassemble them in reverse order.  The steels for the overrunning clutch should be 0.089-0.094' thick after cleanup.  Replace if necessary to maintain proper clutch stack thickness.

Inspect the forward sprag clutch.  When viewed from the smaller hub side, the smaller splined hub should be able to turn clockwise with minimal effort, and should not be able to be turned counterclockwise with any amount of effort or force.  If the sprag is intact, install it into the torque drum. 

Assemble the forward (direct) clutch in reverse order of disassembly.  When installed with the support plate and lock ring, the total clearance of the stack should be between 0.030 and 0.063" as checked with a feeler gauge. Excessive clearance will cause clutch slippage, and inadequate clearance can cause poor release and burning of the clutch plates. 

Assemble the 3-4 clutch and supports in reverse order of disassembly.  When installed with the support plate and lock ring, the total clearance of the stack should be between 0.060 and 0.085" as checked with a feeler gauge.

The entire input power path assembly is depicted here for reference, but refer to the transmission repair manual for specific instructions and details for each section.

4L60E Output Diagram
(Click for larger image)

Install the input drum assembly onto the input planetary gear set and reaction sun shell. This can require some patience and dexterity, as it will be necessary to align and engage two sets of clutch plates with two different driven hubs.  Rotating the input drum to help align the clutches makes the task possible, and up to seven plates on a stock clutch (you should have counted them) need to be aligned to allow full engagement.

Remove the lock ring for the reverse input clutch, then the backing plate, clutch plates and steels.  Remove the Belleville (conical) plate, and inspect as previously directed for wear or damage and replace any parts as necessary. Compress the reverse input clutch spring and remove the retaining ring. Release the compression and remove the spring assembly and piston.  Inspect and replace seals as required.  Reassemble the piston, spring and retainer, then the clutch stack in the order it was removed. Install the backing plate and lock ring, and check the clutch clearance as previously described.  Allowable clearance is 0.040-0.076" for the stack.  Replace clutches or steels as necessary to maintain this clearance.

Inspect and replace the shaft seals on the input drum shaft. Inspect the input drum thrust bearing for damage. 

Install the band.

Reverse Input Drum

Install the reverse input drum by aligning the clutch plates and rotating the drum as necessary to engage all the plates on the inner hub, as well as the outer fingers into the reaction sun shell.   

Assemble and install the 2-4 servo from the outside of the transmission housing, making certain the clamp pin engages the band.  Install the anchor pin for the stationary end of the band and retain it in place with masking tape.

Pump Body Inspection

Remove the pump body bolts and split the pump halves.  Remove the vanes and inspect for wear or damage.  Lift out the vane backing rings and pump rotor and inspect for scoring on either face.

Inspect the pump cavity and end plates for wear of damage.  Inspect the slew ring and springs closely (there are two concentric springs) for damage or distortion.  Make sure the ring can pivot freely against the spring pressure.   Replace any damaged or worn parts as necessary.

Pump Bushing

Drive the front pump bushing out of the housing bore with a suitable tool.  The pump bushing supports the entire mass of the torque converter and can wear quickly.  This is not an area to be overlooked.  Press or drive a new pump bushing into the housing with a suitable tool.

Pump Body Alignment
Assemble the pump with new vanes or reverse the existing vanes if they are serviceable. 

Lightly lubricate the pump rotor and vane support rings, and pack the pump cavity with TransGel or Vaseline to insure fluid pickup once the transmission starts to operate.  

Align the pump halves with a band clamp tool and tighten the body bolts to 18 ft/lb.  Lubricate the new pump bushing. 

Install the pressure regulator valve into the pump housing.  Install the thrust washer on the rear face of the pump housing and retain it in place with TransGel or Vaseline.

Pump Installed
Install the pump into the front of the transmission making sure the gasket is aligned properly, and the pump bushings clear the input shaft without being damaged.  Tighten the body bolts to 18 ft/lb. 

The pump housing will only orient one way, since there is only one area of the pump which has two bolts close together.  The orientation is self explanatory if you observe the bolt pattern. 

There are M10 studs used professionally to help align the pump body for installation, but careful alignment will be sufficient. 

At this point the transmission should be a nearly complete unit minus the valve body. You should be able to turn the turbine (input) shaft clockwise and the internal drag may drive the output shaft in the same direction.  Turning the input shaft counterclockwise will be more difficult, and should result in an opposite rotation of the output shaft.  If the input (turbine) shaft does not react as described, the input sprag may be installed incorrectly or damaged.  Check and rectify this before proceeding further.

There should be between 0.015-0.036" total end play (axial) in the input shaft.  Less than that can mean the pump is being bound or a clutch is not fully engaged, and more than that can mean wear in a drum or thrust washer/bearing which will require shimming. Shim washers are typically placed behind the thrust bearing on the input drum before the reverse input clutch and drum are installed.


Valve body rebuilding will not be covered in detail, since there are several variations.  If you suspect valve body damage, you can remove solenoids and valve spools to inspect them and their bores.  Repairs are typically done by reaming the bore larger, honing, or installing a wear sleeve after reaming, then honing to a finished bore size.  Scuffed or damaged spools must be replaced. 

Aside from rebuilding the valve body, the solenoids should be tested, along with the  temperature sensor and pressure sensors.  A plain ohmmeter will be sufficient.  Your transmission service manual should list the appropriate resistances for the solenoid coils, and normal states of the pressure switches. 

The separator plate should also be inspected closely where the check balls seal.  Repeated operation of the checks will cause the balls to actually pein the openings in the stamped steel plate until the holes are distorted and enlarged. Given enough wear, the balls can go through the plate and render the check system ineffective.  That can completely lock the transmission depending upon which valves are involved.  Any wear should be addressed.  The plate can either be replaced or repaired.  Hard inserts are available to replace the worn areas.  Larger check balls can also be used, but 0.285" is about the safe diameter limit so that the balls do not interfere with flow in the forward direction.

Upper Valve Body Check Balls

Install the single loose upper check ball and accumulator spring, and check that the caged check ball is still in the proper location.   

Install the upper separator plate gasket and plate.  Set the lower gasket onto the separator plate. 

Lower Valve Body Check Balls

Clean the valve body and insert the lower body check balls in their appropriate locations. 

       NOTE: Two balls share one channel near the center of the valve body.

Retain the balls in their respective holes or channels with TransGel or Vaseline. 

Separator Plate

Install the stamped steel plate on the left rear corner of the separator plate and the accumulator body on the right rear corner of the plate.  Insert a few other valve body bolts in various locations to align the gasket and plate properly, then tighten the three M6 X 18 hex head cap screws for the stamped steel plate to 100 in/lb, or about 8 ft/lb.

Tighten the two M6 X 35 and one M6 X 65 hex cap screws for the accumulator to the same torque specification.  

Valve Body InstalledPass the transmission main electrical connector through the hole in the case and fold the wiring harness out of the way.  Insert the linkage rod to the manual valve spool, then position the lower valve body and install all fasteners in their appropriate positions.

NOTE: It is critical to install the bolts in their correct locations.  Installing a bolt which is too long can cause the bolt to seat against the reaction sun shell or reverse input clutch housing/shell and effectively lock the transmission. 

Torque all bolts to 100 in/lb. 

Connect the electrical connectors to the appropriate solenoids and install the TCC solenoid and valve.  Torque those two bolts to 100 in/lb.  Insert the TCC PWM Signal solenoid valve into the remaining valve body bore and clip it in position.  Snap the wiring harness conduit to the valve body bolts.  Install the shift linkage detent arm spring and roller.   


Install a new filter and seal, clean the pan and magnet,  and install it the oil pan.

This would also be a good time to install a drain plug in the pan to ease any future service and routine maintenance.

Set the transmission on the pan and install the adapter bell housing. 

NOTE: The factory used a thread adhesive on these bolts, but given the typical galling and seizure these bolts experience, I've used antiseize compound instead with no adverse results. 

Torque all the bell mounting fasteners to 45 ft/lb.  

Transfer Case

Seal the main transmission electrical connector, oil cooler openings, vent tube, and  input shaft and output shaft areas, then clean the transmission exterior.   

If the vehicle is AWD or 4WD, sealing and cleaning the transfer case would also be advisable.  

Painted and Labelled

Inspect the transmission case seal for the transfer case adapter or the tailshaft housing, and replace the seal as necessary. 

If appropriate, replace the rear bushing in the tailshaft housing and install a new driveshaft yoke seal. Install the tailshaft housing and seal the end with a suitable cap.

The transmission can now be painted and have a new alpha label installed.

In preparation for installation into the vehicle, it would also be good to clean the cross member, lines, and vehicle wiring harness. 

Applying antiseize compound to engine fasteners, chassis and mount bolts, exhaust studs, and other various fasteners is always prudent.

Torque ConverterIf it has not already been done, drain the torque converter completely.  Tip it, slosh it, agitate it, and do whatever is necessary to get all you can out of the converter housing.  A typical converter contains several quarts of fluid, and any contamination which resulted from the transmission failure is likely in the oil within the converter.  Draining it as much as practical reduces the contamination the new filter will experience and helps insure a successful repair.  

When the bulk of the oil is drained from the converter, placing it upside-down over a large steel container (a coffee can works great for this) will allow nearly all the remaining oil to drain out over several hours.

You should also inspect the hub of the converter for visible wear.  This is the part which mates the pump bushing, and they are common wear areas. 

If the converter has high mileage, it may be better to replace it with a new or factory remanufactured unit.   Read the Home page and PARTS and UPGRADES section for the full explanation.

Lubricate the front pump seal and pump bushing with TransGel or transmission fluid, then install the torque converter onto the transmission input shaft. There are two splines to be engaged, and one drive lug (the double slots on the main converter hub) to engage with the pump.  Carefully align the converter with the input shaft and slide it into place.  Rotate and lift/tilt the converter as necessary to engage the splines and pump drive lugs. When installed correctly, the converter should slide all the way back to the point where it contacts the adapter bell.

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