GM Astro/Safari 1985-1996 Repair Guide

Automatic Transmission

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FLUID RECOMMENDATIONS



When adding fluid or refilling the transmission, use Dexron®II (or the latest superceding) automatic transmission fluid for 1985-95 models or Dexron®III for 1996 models. The newer Dexron®III supersedes Dexron®II and may be used in all automatic transmissions covered by this guide.

LEVEL CHECK



See Figures 1, 2, 3, 4 and 5



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Fig. Fig. 1: Most transmission fluid dipsticks on later-model vehicles are labelled ...



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Fig. Fig. 2: ... and a few are hinged (locking into place to seal the guide/filler tube)



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Fig. Fig. 3: As with any dipstick, make sure the fluid level is within the given range(s)



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Fig. Fig. 4: Fluid is added through the dipstick guide/filler tube ...



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Fig. Fig. 5: ... making a funnel mandatory on most models

Before checking the fluid level of the transmission, drive the vehicle for at least 15 miles to warm the fluid. Conversely, if the vehicle has just been driven at high speed for at least the past 1 / 2 hour, or was just pulling a trailer, let the fluid cool down (back toward the center of normal operating range) before checking the fluid.

  1. Place the vehicle on a level surface, then firmly apply the parking brake.
  2.  
  3. Start the engine and move the selector through each range, then place it in P .
  4.  

When moving the selector through each range, DO NOT race the engine.

  1. With the engine running at a low idle (and the GEAR SELECTOR STILL IN P ), remove the transmission's dipstick to check the fluid level.
  2.  

Some late-model vehicles utilize a locking, hinged dipstick. To remove these, simply pull upward on the outer portion of the hinge (straightening out the handle). This will release the dipstick from the guide/filler tube.

  1. The level should be at the Full Hot mark of the dipstick. If not, add fluid using a funnel (to prevent a real mess and possible fire hazard) through the dipstick guide/filler tube. One pint raises the level from Add to Full.
  2.  


CAUTION
Add fluid SLOWLY. DO NOT overfill the transmission, damage to the seals could occur. Overfilling the transmission could also cause small amounts of fluid to be forced back up and out of the tube. Automatic transmission fluid could then be expelled onto hot engine parts, possibly even causing a fire.

The dipstick on some vehicles may have 2 cross-hatched zones (one for HOT and the other for COLD). It is still advisable to check the transmission hot most of the time (it more accurately reflects the level when it matters most), but the COLD zone can be used for an early morning check or as the first refill level during a fluid change.

DRAIN & REFILL

See Figures 6, 7, 8, 9, 10, 11 and 12



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Fig. Fig. 6: Loosen all of the transmission pan retaining bolts ...



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Fig. Fig. 7: ... then remove all but a few at the very rear of the pan



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Fig. Fig. 8: Once most of the fluid has drained, carefully lower the pan from the transmission



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Fig. Fig. 9: Remove the filter for inspection and replacement



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Fig. Fig. 10: The gasket (or rubber seal, depending on the application) must be replaced no matter how good it looks



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Fig. Fig. 11: The magnet at the bottom of the pan should be thoroughly cleaned of all metal particles



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Fig. Fig. 12: Exploded view of the automatic transmission fluid pan and filter

The vehicle should be driven 15 miles to warm the transmission fluid before the pan is removed.

The fluid should be drained while the transmission is warm. Fluid which is at normal operating temperature will flow better, removing more contaminants or impurities than cold fluid.

  1. Raise and support the front of vehicle using jackstands.
  2.  
  3. Place a drain pan under the transmission pan.
  4.  
  5. If necessary, remove the crossmember from the rear of the transmission.
  6.  
  7. Remove the pan bolts from the front and the sides, then loosen the rear bolts 4 turns.
  8.  
  9. Using a small prybar, carefully separate the front of the pan from the transmission. This will allow the pan to partially drain. DO NOT use excessive force when attempting to break the gasket seal. DO NOT bend or otherwise damage the pan and the gasket mating surfaces. If necessary, loosen the bolts a few more turns to allow the pan more play without stressing the flange.
  10.  
  11. Remove the remaining pan bolts and lower the pan from the transmission. Again, be CAREFUL as the pan still contains a decent amount of HOT and MESSY transmission fluid. This is very slimy stuff and if you spill it on yourself (besides possibly being burned) you will feel slimy for days no matter how much you wash.
  12.  

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

  1. Empty the pan, remove the gasket material and clean with a solvent. If you use putty knife to clean the gasket surfaces, be very careful not to score or damage them. Most late-model vehicles utilize a rubber-seal that comes off the pan, with relative ease.
  2.  
  3. As-long-as you've gone through the trouble to drop the pan, you might as well replace the filter. Changing the automatic transmission fluid and filter are the MOST important things you can do to help assure a long, trouble-free transmission life. Well, that and avoiding trying to pull tree stumps on a regular basis.
  4.  
  5. To install the oil pan, use a new gasket and sealant, then reverse the removal procedures. GM recommends that you use Transjel® sealant on the new gasket. Tighten the pan bolts to 97 inch lbs. (11 Nm) in a crisscross pattern.
  6.  
  7. Refill the transmission through the dipstick guide/filler tube. Please refer to the capacities chart later in this section to determine the proper amount of fluid to be added.
  8.  


CAUTION
Add fluid SLOWLY. DO NOT overfill the transmission, damage to the seals could occur. Overfilling the transmission could also cause small amounts of fluid to be forced back up and out of the tube. Automatic transmission fluid could then be expelled onto hot engine parts, possibly even causing a fire.

  1. With the gearshift lever in P , start the engine and let it idle. DO NOT race the engine.
  2.  
  3. Apply the parking brake and move the gearshift lever through each position. Return the lever to P and check the fluid level with the engine idling. The level should be between the 2 dimples on the dipstick, about 1 / 4 in. (6mm) below the ADD mark. On dipsticks that are so marked, the fluid should remain in the COLD zone until the transmission has fully warmed. Add fluid, if necessary.
  4.  
  5. Check the fluid level after the vehicle has been driven enough to thoroughly warm the transmission.
  6.  

PAN & FILTER SERVICE



See Figures 6, 7, 8, 9, 10, 11 and 12

  1. Remove the transmission oil pan. For details, refer to the drain and refill procedures in this section.
  2.  
  3. Remove the screen and the filter from the valve body.
  4.  

When removing the filter from the valve body, be sure the old O-ring is removed with the filter. Sometimes it remains stuck in the pump.

  1. Install a new filter using a new gasket or O-ring.
  2.  

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

  1. To install the oil pan, use a new gasket and sealant, then reverse the removal procedures. Tighten the pan bolts to 87 inch lbs. (11 Nm) in a crisscross pattern. Refill the transmission.
  2.  

 
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