GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Transfer Case

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FLUID RECOMMENDATIONS



When adding fluid or refilling the transfer case, use Dexron® II E on 1994 models and Dexron® III automatic transmission fluid for 1995-99 models covered by this guide.

LEVEL CHECK



See Figure 1



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Fig. Fig. 1: If it is necessary to add fluid, use a small hand operated pump to add the fluid

When checking the fluid, the vehicle must be level. If it was necessary to raise and support the vehicle to access the filler plug, the vehicle must be supported at sufficient points (all wheels or 4 points on the frame) so it is sitting level and is not tilted forward/backward or to one side.

  1. If necessary for access to the filler plug, raise and support the vehicle safely using jackstands, but make sure the vehicle is level.
  2.  
  3. Remove the filler plug (upper one of the 2 plugs) from the rear-side of the transfer case.
  4.  
  5. Using your finger, check the fluid level, it should be level with the bottom of the filler hole.
  6.  
  7. If the fluid level is low, use Dexron® III automatic transmission fluid to bring the fluid up to the proper level. Most parts stores will carry a small, hand operated pump which will greatly ease the task of adding fluid to the transfer case.
  8.  
  9. Install and tighten the filler plug.
  10.  

DRAIN AND REFILL



See Figures 2, 3, and 4



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Fig. Fig. 2: Use a wrench to loosen the drain plug



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Fig. Fig. 3: Remove the drain plug and let the fluid drain



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Fig. Fig. 4: Location of the transfer case fill and drain plugs. The plug size is usually 18mm

  1. Operate the vehicle in four wheel drive in order to warm the fluid to normal operating temperature.
  2.  
  3. If necessary for access to the drain and filler plugs, raise and support the vehicle safely using jackstands. Support the truck so it is level; this is necessary to assure the proper fluid level is maintained when the case is refilled.
  4.  
  5. Position drain pan under transfer case.
  6.  
  7. Use a rag to clean any dirt from around the fill and drain plugs.
  8.  
  9. Remove drain and fill plugs, then drain the lubricant into the drain pan.
  10.  
  11. After the fluid has completely drained, install and tighten the drain plug.
  12.  
  13. Remove the drain pan and dump the fluid into a used transmission fluid storage tank, for recycling purposes.
  14.  
  15. Using Dexron® III automatic transmission fluid, fill transfer case to edge of fill plug opening. Most parts stores will carry a small, hand operated pump which will greatly ease the task of adding fluid to the transfer case.
  16.  
  17. Install and tighten the fill plug.
  18.  
  19. Remove the jackstands and carefully lower the vehicle, then check for proper operation of the transfer case.
  20.  

 
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