Transmission Service

Service the automatic transmission by draining old fluid, replacing the pan gasket and filter, and refilling with fresh transmission fluid.

Warnings

Tools required

Parts

• Automatic transmission pan gasket × 1 — Use OEM specification for Borg-Warner or Chrysler Torqueflite application
• Automatic transmission filter kit × 1 — Use OEM specification for Borg-Warner or Chrysler Torqueflite application

Fluids

• Automatic transmission fluid (Dexron or Type A) — 5 qt

Preparation

1. Park vehicle on level surface and apply parking brake firmly
2. Place wheel chocks behind rear wheels
3. Allow engine and transmission to cool completely if recently operated
4. Raise front of vehicle with floor jack and secure on jack stands under frame rails
5. Verify vehicle is stable before working underneath
6. Position drain pan under transmission pan

Procedure

1. 1

   Locate and inspect transmission pan
   From underneath the vehicle, locate the transmission oil pan at the bottom of the transmission. Inspect for existing leaks or damage. Clean the exterior of the pan and surrounding area with degreaser if heavily soiled.
2. 2

   Loosen transmission pan bolts
   Loosen all transmission pan bolts approximately 2-3 turns. Start at one corner and work around the perimeter. Do not fully remove any bolts yet. This allows fluid to begin draining slowly from one corner.
3. 3

   Drain transmission fluid
   Carefully pry down one corner of the transmission pan slightly to allow fluid to drain into the catch pan. Control the flow by adjusting how much you pry the pan down. Once draining slows, remove the remaining bolts except for two at opposite corners. Support the pan by hand and remove the final two bolts, then lower the pan carefully to avoid spilling remaining fluid.
4. 4

   Remove transmission filter
   Locate the transmission filter attached to the valve body inside the transmission. The filter is typically held by 2-3 bolts or may have a press-fit neck. Remove the retaining bolts if equipped and pull the filter straight down. Some fluid will drain from the filter, so keep the drain pan positioned below.
5. 5

   Clean transmission pan and magnet
   Thoroughly clean the inside of the transmission pan with solvent and shop rags. Inspect the magnetic drain plug or magnet in the pan for metal shavings. Small amounts of fine material are normal, but large metal particles or chunks indicate internal transmission wear. Clean the magnet completely.
6. 6

   Remove old gasket material
   Use a gasket scraper to carefully remove all old gasket material from both the transmission pan mounting surface and the transmission case sealing surface. Do not gouge or scratch the metal surfaces. Ensure all surfaces are completely clean and dry.
7. 7

   Install new transmission filter
   Position the new transmission filter and align it with the mounting holes or press-fit neck on the valve body. If bolt-on type, install and hand-tighten the retaining bolts, then torque to specification per the filter kit instructions (typically 35-45 in-lbs). If press-fit type, push firmly until fully seated.
8. 8

   Install new pan gasket
   Position the new gasket on the transmission pan. Verify all bolt holes align correctly. Some gaskets have adhesive backing; if yours does not, you may use a small amount of gasket sealer at the corners only to hold the gasket in place during installation.
9. 9

   Reinstall transmission pan
   Carefully lift the transmission pan with gasket into position against the transmission case. Start all bolts by hand to ensure proper alignment. Tighten bolts in a crisscross pattern, working from the center outward. Torque to 12-15 ft-lbs in multiple passes. Do not overtighten as this will distort the pan and cause leaks.
10. 10

    Lower vehicle and add transmission fluid
    Remove jack stands and lower the vehicle to the ground. Locate the transmission dipstick tube. Using a long-neck funnel, add 4 quarts of the appropriate automatic transmission fluid through the dipstick tube. The 1970 AMC typically uses Type A or Dexron fluid; verify specification for your transmission.
11. 11

    Start engine and circulate fluid
    Start the engine and allow it to idle. With the parking brake applied and foot on the brake pedal, shift through all gear positions (P-R-N-D-2-1), pausing 2-3 seconds in each position. Return to Park. This circulates fluid through the transmission and torque converter.
12. 12

    Check and adjust fluid level
    With the engine idling and transmission in Park, check the fluid level on the dipstick. The level should be between the ADD and FULL marks. Add fluid in half-quart increments as needed. Recheck level after each addition. Do not overfill.
13. 13

    Test drive and recheck
    Take the vehicle for a short test drive of 5-10 minutes to fully warm the transmission and circulate fluid. Upon return, with engine idling and transmission in Park on level ground, recheck the fluid level and adjust as necessary. Inspect under the vehicle for any leaks from the pan gasket.

Reassembly

1. Ensure all transmission pan bolts are torqued to specification in a crisscross pattern
2. Verify transmission fluid level is correct with engine at operating temperature
3. Dispose of used transmission fluid and filter properly at a recycling center

Verification

• With engine at operating temperature and idling in Park, transmission fluid level should read between ADD and FULL marks on dipstick
• No leaks visible from transmission pan after test drive
• Transmission shifts smoothly through all gears without slipping or harsh engagement
• Transmission fluid on dipstick should appear red or pink and smell normal, not burnt

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