Cadillac 26064030 Seal, Differential Drive Pinion Gear

Loosen the rear wheel lug nuts, raise the rear of the vehicle, and support it securely on jackstands while blocking the front wheels to prevent rolling. Remove the wheels and disconnect the driveshaft from the differential pinion flange, fastening it out of the way. Rotate the pinion a few times by hand and use a beam-type or dial-type inch-pound torque wrench to check the torque required to rotate the pinion, recording the value for later use. Mark the relationship of the pinion flange to the shaft and count the number of exposed threads on the shaft. Use a chain wrench to keep the companion flange from moving while loosening the self-locking pinion nut, then remove the pinion nut. Withdraw the flange, using a two-jaw puller if necessary, and avoid prying or hammering behind the flange. Pry out and discard the old seal, then lubricate the lips of the new seal and fill the space between the seal lips with wheel bearing grease before tapping it evenly into position with a seal installation tool or a large socket, ensuring it enters the housing squarely and to its full depth. Install the pinion flange, aligning it with the marks made, and tighten the pinion nut to draw the flange into place without hammering. Apply a bead of RTV sealant to the ends of the splines visible in the center of the flange, then install the washer and a new pinion nut, tightening it until the recorded number of threads are exposed. Measure the torque required to rotate the pinion and tighten the nut in small increments until it matches the recorded figure, compensating for the drag of the new oil seal by tightening a little more until the rotational torque exceeds the earlier recording by 5 in-lbs. Finally, reinstall all previously removed components by reversing the removal steps and tightening all fasteners to their specified torque values.

The driveshaft needs to be disconnected from the differential pinion flange.

Before installing the new pinion nut, RTV sealant should be applied to the ends of the splines visible in the center of the flange.

After installing the new seal and pinion nut, all components should be reinstalled and all fasteners should be tightened to their specified torque values.

The first step is to loosen the wheel lug nuts and raise the front or rear of the vehicle on jackstands.