Ford Thunderbird/Cougar 1983-1997 Repair Guide

Drive Axle



Like the manual transmission, the rear axle fluid should be checked every six months or 6000 miles (9654 km). A filler plug is provided near the center of the rear cover or on the upper (driveshaft) side of the gear case. Add SAE 85W/90/95 gear lube as required.


See Figures 1, 2 and 3

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Fig. Fig. 1: Use a proper sized ratchet to loosen the filler plug

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Fig. Fig. 2: If necessary, add the proper fluid through the filler hole

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Fig. Fig. 3: When installing the plug, first thread it in by hand

  1. Remove the plug and check to ensure that the fluid level is even with the bottom of the filler hole.

  1. Add SAE 85W/90/95 gear lube as required.

  1. If the vehicle is equipped with a limited slip rear axle, add the required special fluid.

  1. Install the filler plug but do not overtighten.


Normal maintenance does not require changing the rear axle fluid. However, to do so, remove the rear drain plug (models equipped), the lower two cover bolts, or the cover. Catch the drained fluid in a suitable container.

If the rear cover was removed, clean the mounting surfaces of the cover and rear housing. Install a new gasket (early models) or (on late models) apply a continuous bead of Silicone Rubber Sealant (D6AZ-19562-AA or BA or the equivalent) around the rear housing face inside the circle of bolt holes. Install the cover and tighten the bolts to specifications. Parts must be assembled within a half hour after the sealant is applied. If the fluid was drained by removing the two lower cover bolts, apply sealant to the bolts before reinstallation. Fill the rear axle through the filler hole with the proper lube. Add friction modifier to limited slip models if required.