Transmission Input Shaft Bearing

Replace the transmission input shaft bearing by removing the transmission, disassembling the front pump housing, pressing out the old bearing, and installing a new bearing with proper clearances.

Warnings

Tools required

Parts

• Transmission input shaft bearing × 1 — Use OEM specification
• Transmission front pump seal × 1 — Use OEM specification
• Transmission pan gasket × 1 — Use OEM specification
• Transmission filter × 1 — Use OEM specification
• Transmission to engine gasket × 1 — Use OEM specification
• Transmission drain plug washer × 1 — Use new crush washer
• RTV silicone sealant (transmission safe) × 1 — ACDelco 88901148 or equivalent

Fluids

• ACDelco Dexron VI ATF — 11.5 qt

Preparation

1. Park vehicle on level surface and set parking brake.
2. Disconnect negative battery cable to prevent starter engagement.
3. Raise vehicle on lift or support securely on jack stands at frame rails.
4. Remove rear driveshaft and mark U-joint orientation for reassembly.
5. Drain transmission fluid from drain plug and transmission pan into appropriate container.
6. Remove transmission cooler lines and plug openings to prevent contamination.
7. Install engine support fixture or safely support engine from above to prevent movement when transmission is removed.
8. Prepare clean workbench area for transmission disassembly with adequate lighting.

Procedure

1. 1

   Remove transmission pan and filter
   Remove all transmission pan bolts in criss-cross pattern to prevent warping. Lower pan carefully as residual fluid will drain. Remove transmission filter by pulling straight down from valve body. Clean pan thoroughly and inspect for metal debris indicating internal wear.
   Torque spec

   Pan Bolts20 Nm (15 lb-ft)
2. 2

   Disconnect transmission electrical connections and linkages
   Disconnect transmission wiring harness connectors including speed sensors, solenoid pack, and temperature sensor. Remove shift linkage cable from transmission lever and bracket. Disconnect any ground straps attached to transmission case.
3. 3

   Support and remove transmission
   Position transmission jack under transmission pan and secure with safety chain. Remove crossmember mounting bolts. Remove bellhousing bolts securing transmission to engine block. Carefully pull transmission straight back to disengage torque converter from flexplate. Lower transmission slowly ensuring all connections are clear.
   ⚠️Transmission must be secured to jack with chain or strap. Ensure torque converter is secured or removed to prevent falling during removal.
   Torque spec

   Mounting Bolts76 Nm (56 lb-ft)
4. 4

   Remove torque converter and external components
   Pull torque converter straight out of transmission input shaft and front pump assembly. Drain remaining fluid from converter. Remove any external sensors, speed sensor, or wiring harness brackets still attached to transmission case. Clean exterior of transmission thoroughly before disassembly.
5. 5

   Remove transmission pump assembly
   With transmission on bench, front facing up, remove all pump cover bolts securing the front pump assembly to the transmission case. Use gentle prying if needed to break seal. Carefully pull pump assembly straight out, noting position of any alignment dowels or gaskets. Remove and discard front pump gasket.
   ⚠Do not pry between aluminum sealing surfaces as this may cause damage requiring case replacement.
   Torque spec

   Cover Screws14 Nm (10 lb-ft)
6. 6

   Disassemble front pump housing
   Secure pump assembly in bench vise using soft jaws to prevent damage. Remove pump cover bolts and separate pump cover from pump body. Remove gerotor pump assembly and set aside. Note orientation of all components for reassembly. Clean all components thoroughly with solvent.
7. 7

   Remove input shaft bearing
   Inspect input shaft bearing for visible wear, pitting, or discoloration. Use snap ring pliers to remove bearing retaining snap ring from pump housing. Using bearing puller or hydraulic press with appropriate support fixture, press bearing out of pump housing from the rear. Inspect bearing bore for scoring or damage that would prevent proper new bearing installation.
   ⚠Support pump housing properly during pressing operation to prevent cracking or distortion of aluminum housing.
8. 8

   Prepare and install new input shaft bearing
   Clean bearing bore thoroughly with solvent and compressed air. Measure bearing bore diameter and new bearing outer diameter to verify proper fit (typical clearance 0.0005-0.0015 inches). Place new bearing in freezer for 30 minutes to aid installation. Using bearing driver or press with proper pilot, press new bearing squarely into housing until fully seated against shoulder. Install new retaining snap ring and verify it is fully seated in groove.
   ⚠Apply press force only to outer bearing race. Pressing on inner race or rollers will damage bearing.
9. 9

   Check bearing preload and endplay
   Install input shaft into pump assembly with new bearing. Using dial indicator, measure input shaft endplay (specification typically 0.010-0.035 inches). Check that shaft rotates smoothly without binding or excessive looseness. Verify bearing is not cocked or misaligned. Replace front pump seal using seal installation tool.
10. 10

    Reassemble front pump assembly
    Install gerotor pump assembly into pump body in correct orientation (match previous notes). Apply thin coat of ATF to pump components. Install pump cover with new gasket or RTV sealant as per OEM specifications. Torque pump cover bolts in crisscross pattern to specification.
    Torque spec

    Cover Screws14 Nm (10 lb-ft)
11. 11

    Install pump assembly to transmission
    Apply thin coat of assembly lube or ATF to pump bushing and seal lip. Install new pump gasket on transmission case. Align pump assembly with case ensuring proper engagement with reaction shaft support splines. Install pump mounting bolts and torque in crisscross pattern to specification.
    ⚠Pump assembly must slide in smoothly. Forcing indicates misalignment which can damage internal splines or bushing.
    Torque spec

    Cover Screws14 Nm (10 lb-ft)
12. 12

    Install torque converter and verify engagement
    Install torque converter into front pump assembly, rotating to engage pump drive, turbine shaft, and stator support (three distinct engagement clicks or drops). Measure converter installation depth from bellhousing surface to converter mounting lugs. Depth should be minimum 1/2 inch recessed to ensure full engagement before mating to flexplate.
    ⚠️Improperly seated torque converter will appear to install correctly but will damage pump assembly when flexplate bolts are tightened.
13. 13

    Install transmission to engine
    Apply thin coat of high-temp grease to torque converter pilot hub. Install new transmission to engine gasket. Raise transmission into position using transmission jack, aligning torque converter with flexplate and dowel pins with engine block. Install bellhousing bolts and torque to specification. Rotate crankshaft to access all torque converter to flexplate bolts through starter opening. Install flexplate bolts and torque in star pattern to specification.
    ⚠Verify torque converter is fully engaged before tightening bellhousing bolts. Converter should rotate freely and not be pulled into pump during installation.
    Torque spec

    Mounting Bolts76 Nm (56 lb-ft)

    Flywheel Bolts95 Nm (70 lb-ft)
14. 14

    Reinstall crossmember and complete external connections
    Install transmission crossmember and torque mounting bolts to specification. Reconnect transmission cooler lines using new O-rings if equipped. Reconnect all electrical connectors, ground straps, and shift linkage. Install driveshaft ensuring U-joint phasing matches original orientation.
    Torque spec

    Mounting Bolts76 Nm (56 lb-ft)
15. 15

    Install new filter, pan, and refill transmission
    Install new transmission filter to valve body. Clean pan and transmission case mating surface thoroughly. Install new pan gasket or apply RTV bead as specified. Install transmission pan and torque bolts in criss-cross pattern to specification. Install drain plug with new crush washer and torque to specification. Fill transmission with correct amount of Dexron VI ATF through dipstick tube.
    Torque spec

    Pan Bolts20 Nm (15 lb-ft)

    Drain Plug42 Nm (31 lb-ft)

Reassembly

1. Verify all bellhousing and crossmember bolts are torqued to specification.
2. Ensure all electrical connectors are fully seated with locking tabs engaged.
3. Double-check transmission cooler line connections for proper seating and security.
4. Verify driveshaft U-joint orientation matches original position to prevent vibration.
5. Reconnect negative battery cable.

Verification

• With vehicle still raised, start engine and verify no transmission fluid leaks from pan, drain plug, pump seal, or cooler lines.
• Check transmission fluid level with engine at operating temperature and in park on level ground. Add fluid as needed to reach proper level on dipstick.
• With brakes applied, shift through all gear ranges (P-R-N-D-L) and verify smooth engagement with no harsh shifting or slipping.
• Test drive vehicle through all gears confirming smooth shifts, proper engagement, and no abnormal noises from transmission.
• Recheck fluid level after test drive and top off if necessary. Inspect for leaks after test drive.
• Monitor transmission operation for first 100 miles and recheck fluid level. New bearing should eliminate any input shaft whine or noise that was present before repair.

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