FLUID LEVEL CHECK
See Figures 1, 2, 3 and 4
Check the automatic transmission fluid level at least every 6000 miles (9600 km) for 1973-79 vehicles; 15,000 miles (24,000 km) for 1980-88 vehicles.The dipstick is in the right rear of the engine compartment. The fluid level should be checked only when the transmission is hot (normal operating temperature). The transmission is considered hot after about 20 miles of highway driving.
- Park the truck on a level surface with the engine idling. Shift the transmission into P and set the parking brake.
- Remove the dipstick, wipe it clean and reinsert if firmly. Be sure that it has been pushed all the way in. Remove the dipstick and check the fluid level while holding it horizontally. With the engine running, the fluid level should be between the H and L marks on 1973-87 models. 1988-88 models have a HOT and a COLD side to the dipstick. On 2wd models, the fluid level should be between the two hash marks on the HOT side or between the two notches on the COLD side. On 4wd models, the fluid level should be within the cross-hatched area on the HOT or COLD sides.
- If the fluid level is below the L mark on 1973-87 models, below the lower hash mark (HOT) or lower notch (COLD) on 1988-88 2wd models, or not within the cross-hatched area on either side of the dipstick on 1988 4wd models, pour DEXRON®II ATF into the dipstick tube. This is easily done with the aid of a funnel. Check the level often as you are filling the transmission. Be extremely careful not to overfill it. Overfilling will cause slippage, seal damage and overheating. Approximately one pint of ATF will raise the level from one notch to the other.
Always use the proper transmission fluid when filling your truck's transmission. All models use DEXRON®II. Always check with the owner's manual to be sure. NEVER use Type F in a transmission requiring DEXRON® or vice versa, as severe damage will result.
DRAIN AND REFILL
The automatic transmission fluid should be changed at least every 25,000-30,000 miles (40,000-48,000 km). If the truck is normally used in severe service, such as stop-and-go driving, trailer towing or the like, the interval should be halved. The fluid should be hot before it is drained; a 20 minute drive will accomplish this.Pan and Filter Service
See Figures 5 and 6
- There is no drain plug; the fluid pan must be removed. Partially loosen the pan retaining screws until the pan can be pulled down at one corner. Lower a corner of the pan and allow all fluid to drain out.
- After the pan has drained completely, remove the pan retaining screws and then remove the pan and gasket.
- Clean the pan thoroughly and allow it to air dry. If you wipe it out with a rag you run the risk of leaving bits of lint in the pan which will clog the tiny hydraulic passages in the transmission.
- Install the pan using a new gasket. If you decide to use sealer on the gasket, apply it only in a very thin bead running to the outside of the pan screw holes. Tighten the pan screws evenly in rotation from the center outwards, to 3-5 ft. lbs. (4-7 Nm).
- It is a good idea to measure the amount of fluid drained from the transmission to determine the correct amount of fresh fluid to add. This is because some parts of the transmission may not drain completely and using the dry refill amount specified in the Capacities chart could lead to overfilling. Fluid is added only through the dipstick tube. Use only the proper automatic transmission fluid; do not overfill.
- Replace the dipstick after filling. Start the engine and allow it to idle. DO NOT race the engine.
- After the engine has idled for a few minutes, shift the transmission slowly through the gears and then return it to P . With the engine still idling, check the fluid level on the dipstick. If necessary, add more fluid to raise the level to where it is supposed to be.