Chrysler Full-Size Trucks 1989-1996 Repair Guide

Drive Axle (Rear and/or Front)



Multipurpose gear lubricant meeting API GL-5 requirements or MOPAR hypoid lubricant can be used in conventional differential axles. Limited slip units, except in the 9 3 / 4 in. and 10 1 / 2 in. axles, must use MOPAR hypoid lubricant. A MOPAR friction modifier additive is available to cure chatter and noise in these units.

The 9 3 / 4 in. and 10 1 / 2 in. limited slip units must use MOPAR Sure-Grip lubricant. Gear lubricant viscosity depends on the anticipated temperatures: use SAE 140 above 2°F (32°C), SAE 2 for 10-2°F (-12°-32°C), and SAE 80 below 10°F (-12°C). The factory fill is normally SAE 2. Multi-viscosity lubricants may be used. For more information on rear axle identification, please refer to the serial number identification information earlier in this section.


See Figure 1

To check the axle lubricant level, remove the axle filler plug with the truck parked on a level surface.

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Fig. Fig. 1: Remove the filler plug to check the axle lubricant level

You can use a finger for a dipstick, being careful of sharp threads. If necessary, add lubricant with a suction gun. The lubricant level should be 1 / 2 in. (13mm) below the filler plug hole on 8 1 / 4 , 8 3 / 8 and 8 3 / 4 in. axles, or at the bottom of the filler plug hole on all the rest.


See Figures 2 and 3

Axles on Plymouth and Dodge trucks are not equipped with drain plugs. The old lubricant must be drained by removing the differential housing cover. Use a bead of RTV silicone sealant as a gasket.

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Fig. Fig. 2: Apply sealant as shown when replacing the axle cover

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Fig. Fig. 3: Common rear axle filler plugs

Sealant should be applied as follows:

  1. Scrape away any remains of the paper gasket or old traces of sealant, as applicable.
  3. Clean the cover surface with mineral spirits. Any axle lubricant on the cover or axle housing will prevent the sealant from taking.
  5. Apply a 1 / 16 - 3 / 32 in. (1.6-2.4mm) bead of sealant to the clean and dry cover flange. Apply the bead continuously along the bolt circle of the cover, looping inside the bolt holes as shown.
  7. Allow the sealant to air dry.
  9. Clean the carrier gasket flange (if solvent is used, allow it to air dry). Install the cover. If, for any reason, the cover is not installed within 20 minutes of applying the sealant, remove the sealant and start over.