Transmission Rebuild - Automatic

Complete disassembly, inspection, cleaning, and rebuild of the automatic transmission (likely BorgWarner M-11 or Chrysler TorqueFlite 727) for the 1970 AMC Rebel Machine, including replacement of all wear components, seals, and gaskets.

Warnings

Tools required

Parts

• Automatic transmission master rebuild kit × 1 — Use OEM specification for BorgWarner M-11 or TorqueFlite 727
• Torque converter seal × 1 — Use OEM specification
• Front pump bushing × 1 — Use OEM specification
• Governor seal kit × 1 — Use OEM specification
• Rear bushing × 1 — Use OEM specification
• Modulator valve (if applicable) × 1 — Use OEM specification
• Transmission filter × 1 — Use OEM specification
• Flexplate-to-converter bolts × 1 — Use OEM specification
• Transmission pan gasket or RTV sealant × 1 — Use OEM specification

Fluids

• Automatic transmission fluid (Type A or Dexron) — 12 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable
3. Raise vehicle on lift or jack stands rated for vehicle weight with proper support points
4. Mark driveshaft-to-differential flange orientation for reassembly
5. Remove driveshaft and plug transmission output to prevent fluid loss
6. Disconnect speedometer cable, shift linkage, and neutral safety switch connector
7. Disconnect transmission cooler lines and plug to prevent contamination
8. Support engine with support bar or chain hoist to prevent engine drop when transmission removed
9. Remove crossmember supporting transmission mount
10. Mark flexplate-to-torque converter relationship before separation
11. Support transmission with transmission jack before removing bellhousing bolts
12. Clear adequate bench space in clean environment for transmission disassembly and parts inspection

Procedure

1. 1

   Remove transmission from vehicle
   With transmission properly supported on transmission jack, remove all bellhousing-to-engine bolts. Carefully slide transmission rearward ensuring torque converter stays with transmission (use a retaining strap if necessary). Lower transmission from vehicle and move to clean workbench. Drain all remaining fluid from transmission and torque converter.
2. 2

   External component removal
   Remove transmission pan and filter. Remove modulator valve (if equipped). Remove governor cover and governor assembly. Remove output shaft yoke or flange. Remove speedometer drive gear and housing. Remove manual valve linkage and external levers. Clean exterior of transmission case thoroughly before internal disassembly.
3. 3

   Remove valve body assembly
   With transmission pan-side up, carefully remove all valve body mounting bolts in sequence (typically remove accumulator pistons first if accessible). Note exact positions of different length bolts. Carefully lower valve body assembly while noting position of manual valve and throttle valve links. Tag all springs and check balls with their positions. Place valve body on clean workbench or valve body stand for later disassembly.
4. 4

   Remove front pump and input shaft
   Remove front pump retaining bolts. Use slide hammer or carefully pry pump assembly from case (some designs require tapping case while pulling pump). Remove pump gasket or seal. Withdraw input shaft and forward clutch assembly as a unit. Mark clutch pack orientation. Remove thrust washers and note their positions and thicknesses for endplay measurement later.
5. 5

   Remove clutch packs and planetary gear sets
   Remove forward and direct (or high-reverse) clutch assemblies. Note selective snap ring positions. Remove planetary gear assemblies (typically front and rear planetaries and sun gear). Remove intermediate band and servo assembly. Tag all components with their orientation and position. Measure and record all endplay measurements before further disassembly.
6. 6

   Remove output shaft and rear components
   Remove output shaft assembly from case. Remove parking pawl actuating rod and pawl assembly. Remove low-reverse or rear clutch assembly. Remove reaction shaft support and bearing assembly. Remove all remaining snap rings, thrust washers, and bearings. Keep all components organized by assembly.
7. 7

   Disassemble and inspect clutch packs
   Using spring compressor tool, compress clutch pack springs and remove retaining snap rings. Remove pressure plates, clutch discs, and steel plates in order. Inspect all friction discs for glazing, burning, or wear. Check steel plates for warping and scoring. Inspect piston seals for cuts or deterioration. Measure clutch pack clearances. Replace all seals and friction materials per rebuild kit. Check clutch housings for cracks or wear.
8. 8

   Disassemble and inspect front pump
   Separate pump housing from stator support. Remove pump gears and inspect for scoring or wear. Check pump body bushing for wear using inside micrometer (replace if worn beyond specification, typically 0.003 inch clearance maximum). Inspect stator support for scoring or bushing wear. Replace pump seal and all pump gaskets. Inspect pump gear teeth and pocket for wear patterns.
9. 9

   Disassemble and inspect valve body
   Working on clean surface, systematically disassemble valve body separator plate and valves. Remove each valve, spring, and plug while documenting position and orientation. Inspect all valve bores for scoring or wear. Check all valves for free movement (they should drop freely under their own weight in bore). Inspect separator plate gaskets for proper check ball positioning. Clean all passages with compressed air and solvent. Replace all valve body gaskets and seals per rebuild kit.
10. 10

    Clean and inspect transmission case
    Thoroughly clean transmission case with solvent and compressed air. Inspect case for cracks, stripped threads, or damage. Check all fluid passages are clear. Inspect bushing bores for wear or scoring. Replace bushings if worn beyond specification using proper bushing drivers. Inspect case vent and ensure it is clear. Check parking pawl and shaft for wear.
11. 11

    Inspect and measure hard parts
    Measure all planetary gear endplay with feeler gauges. Check pinion gear bushings for wear. Inspect all thrust washers and selective spacers for wear (replace if less than minimum thickness). Measure input and output shaft bushing surfaces with micrometer for wear. Inspect all snap ring grooves for damage. Check all gear teeth for chips or excessive wear. Verify reaction shaft support splines are not worn or damaged.
12. 12

    Reassemble clutch packs with new components
    Install new piston seals using petroleum jelly as assembly lubricant (never use regular grease). Install pistons into clutch drums carefully to avoid seal damage. Install new friction discs (soak in ATF for 15 minutes before installation) alternating with steel plates per factory specification. Install pressure plates and compress springs using spring compressor. Install new snap rings ensuring proper seating. Measure and verify clutch pack clearance using feeler gauge (typically 0.025-0.060 inch depending on clutch pack). Air test each clutch assembly using air pressure test plate to verify piston operation and seal integrity.
13. 13

    Reassemble transmission internal components
    Install new rear bushing using proper driver. Install output shaft assembly with new seals. Install reaction shaft support with new gasket or seal. Install low-reverse or rear clutch assembly. Install planetary gear sets with proper thrust washers coated in petroleum jelly. Install intermediate band and adjust servo if applicable. Install direct and forward clutch assemblies in proper orientation. Install input shaft assembly. Verify all selective snap rings are properly seated.
14. 14

    Install front pump and set endplay
    Install new front pump bushing if required. Reassemble front pump with new seal and gasket. Select proper thrust washer thickness to achieve proper input shaft endplay (typically 0.010-0.035 inch depending on transmission model). Use dial indicator to measure endplay. Install pump assembly using alignment tools or guide studs to prevent seal damage. Install and hand-tighten pump bolts in star pattern, then torque per factory specification (typically 10-18 ft-lbs but verify for your specific transmission).
15. 15

    Reassemble valve body and install in case
    Reassemble valve body with all new gaskets, seals, and separator plate gaskets from rebuild kit. Ensure all check balls are in correct positions per service manual diagram. Verify all valves move freely. Install new filter. Position valve body in case while carefully aligning manual valve with manual lever. Install accumulator pistons with new seals. Install all valve body bolts in proper sequence and torque per specification (typically 35-50 inch-pounds). Install governor assembly with new seals. Install modulator valve if equipped.
16. 16

    Install extension housing and external components
    Install new extension housing seal and gasket. Install extension housing and torque bolts per specification. Install output shaft yoke or flange with new seal. Install speedometer drive gear and housing with new O-ring. Install manual linkage and external levers. Install new torque converter seal in front pump. Verify parking pawl operation. Install new transmission pan gasket or apply RTV sealant per specification and install pan with new filter.
17. 17

    Install transmission in vehicle
    Inspect torque converter for damage or wear (replace if questionable). Install torque converter on input shaft verifying proper engagement (converter should seat in multiple stages with distinct clicks). Secure converter with retaining strap. Apply light coat of high-temp grease to torque converter pilot. Carefully raise transmission into position while aligning with engine using transmission jack. Install all bellhousing-to-engine bolts and torque per factory specification (typically 40-50 ft-lbs). Install crossmember and transmission mount. Remove engine support.
18. 18

    Connect external components and fill transmission
    Align and connect driveshaft per alignment marks made during disassembly. Connect transmission cooler lines (replace if showing deterioration). Connect shift linkage and adjust per specification. Connect neutral safety switch. Connect speedometer cable. Reconnect negative battery cable. Add appropriate automatic transmission fluid (Type A or Dexron depending on year specification) through dipstick tube. Start with approximately 6 quarts, then add more after running engine.

Reassembly

1. Verify all snap rings are fully seated in their grooves throughout transmission
2. Ensure all thrust washers remained in position during assembly
3. Confirm proper clutch pack clearances were achieved on all clutch assemblies
4. Verify all bolts are torqued to proper specification (consult factory service manual for your specific transmission model)
5. Double-check all external connections are secure before initial start-up

Verification

• With engine running and transmission in Park, check fluid level and condition (should be clean and red)
• Check for external leaks around pan, pump seal, and cooler lines
• Perform shift linkage adjustment and verify all gear positions engage properly on shifter
• With parking brake applied and wheels chocked, run through all gear ranges and verify engagement without excessive delay or harshness
• Perform careful test drive checking for proper shift points, no slippage, smooth engagement, and proper downshifts
• Recheck fluid level after transmission reaches operating temperature (between 160-200°F)
• Verify no unusual noises in any gear range
• Check shift linkage allows engine to start only in Park and Neutral positions
• Monitor for leaks after test drive and recheck all external connections
• Verify transmission cooler flow by feeling cooler lines for temperature differential during operation

More procedures for this vehicle