GM Cadillac 1967-1989 Repair Guide

Rear Axle (Rear Wheel Drive Only)

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FLUID LEVEL CHECK



See Figures 1, 2, 3, 4 and 5

The oil in the differential should be checked at least every 7,500 miles.

  1. Park the car on a level surface and remove the filter plug from the front side of the differential.
  2.  
  3. If the oil begins to trickle out of the hole when the plug is removed, the differential is full. If no lubricant trickles out, carefully insert your finger (watch out for sharp threads) into the hole and check that the oil is up to the bottom edge of the filler hole.
  4.  
  5. If not, add oil through the hole until the level is at the edge of the hole. Most gear oils come in a plastic squeeze bottle with a nozzle end, which makes adding lubricant simple. You can also use a common turkey baster for this job. Use only standard GL-5 hypoid-type gear oil-SAE 80W or SAE 80W/90.
  6.  

On all models equipped with a positraction/limited slip differential, GM recommends that you use only special GM lubricant available at your local Cadillac parts department.

DRAIN AND REFILL

There is no recommended change interval for the rear axle lubricant, but it is always a good idea to change the lube if you have purchased the car used or if it has been driven in water high enough to reach the axle.

  1. Park the car on a level surface and set the parking brake.
  2.  
  3. Remove the rear axle filler plug on the front side of the differential housing.
  4.  
  5. Place a large drain pan underneath the rear axle.
  6.  
  7. Unscrew the retaining bolts and remove the rear axle cover. The axle lubricant will now be able to drain into the container.
  8.  
  9. Using a new cover gasket and sealant, install the axle cover. Tighten the retaining bolts in a crisscross pattern.
  10.  
  11. Refill the axle with the proper quantity (see Capacities chart in this section) of SAE 80W or SAE 80W-90 GL-5 gear lubricant. Replace the filler plug, take the car for a short ride and check for any leaks around the plug or rear cover.
  12.  



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Fig. Fig. 1: The fluid level in the differential should be up to the edge of the filler hole (large arrow)



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Fig. Fig. 2: Remove the filler plug to check the lubricant level in the rear axle



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Fig. Fig. 3: Removing the filler plug in the rear axle with tool



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Fig. Fig. 4: Removing the filler plug



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Fig. Fig. 5: Adding rear axle fluid

 
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