GM Corvette 1963-1982 Repair Guide

Fluid Pan



The fluid should be drained while the transmission is warm.

  1. Using a jack, raise the front of the vehicle and support it safely with jackstands. If the transmission pan has no drain plug, visually check that you can gain access to all of the transmission pan bolts. If you can, proceed to step 8; if not, proceed to step 2.
  3. Place a jack under the transmission with a block of wood (a piece of a 2X4 will do) between the jack and the transmission pan.
  5. Raise the jack until the wood block contacts the transmission pan.
  7. Remove the crossmember-to-transmission mount bolts and the crossmember-to-frame bolts.
  9. Raise the transmission SLIGHTLY-just enough to take the weight of the transmission off of the crossmember.
  11. Turn the crossmember sideways and remove it.
  13. Place a jackstand close to the transmission tailshaft. Lower the jack until the transmission rests on the stand. Remove the jack and the wood block.
  15. Place a drain pan under the transmission pan. If the pan has a drain plug, remove it and allow the fluid to drain.
  17. If the pan does not have a drain plug, remove the pan bolts from one side of the pan and loosen the rest of the bolts. This will allow the pan to partially drain. Remove the remaining pan bolts and carefully lower the pan away from the transmission.

If the transmission fluid is dark or has a burnt smell, transmission damage is indicated. Have the transmission checked professionally.

If the pan sticks, carefully tap sideways on the pan with a rubber mallet or a plastic hammer to break the pan loose. DO NOT dent the pan. Avoid prying the pan off with a screwdriver-this can bend the pan or crack the transmission case.

  1. Empty the pan, remove the gasket material, and clean the pan with solvent (carburetor cleaner works well).
  3. Remove any gasket material which may remain on the transmission case.
  5. Remove the transmission filter from the valve body. The filter may have either a fibrous or screen filtering element and is retained by one or two fasteners.

To install:
  1. Install a new filter using a new gasket or O-ring (TH400).

If the transmission uses a filter having a fully exposed screen, it may be cleaned and re-used.

  1. Install the pan using a new gasket. Tighten the bolts to 12-14 ft. lbs. in a criss-cross pattern. Recheck the bolt torque after all of the bolts have been tightened once.
  3. Add either Dexron or Dexron II transmission fluid through the filler tube. See the Capacities Chart to determine the proper amount of fluid to be added.

DO NOT OVERFILL the transmission; foaming of the fluid and subsequent transmission damage due to slippage will result.

  1. With the gearshift lever in PARK, start the engine and let it idle. Do not race the engine.
  3. Move the gearshift lever through each position, holding the brakes. Return the lever to PARK, and check the fluid level with the engine idling. The level should be between the two dimples on the dipstick, about 1 / 4 in. below the ADD mark. Add fluid, if necessary.
  5. Check the fluid level after the vehicle has been driven enough to thoroughly warm up the transmission. Details are given under Fluid Level Checks. If the transmission is overfilled, the excess must be drained off. Use a suction pump, if necessary.