Buick 26033578 Seal, Differential Drive Pinion Gear

Raise the rear of the vehicle and support it securely on jackstands. Block the front wheels to keep the vehicle from rolling off the stands. Disconnect the driveshaft and fasten it out of the way. On semi-floating axles, use an inch-pound torque wrench to check the torque required to rotate the pinion. Record it for use later. Scribe or punch alignment marks on the pinion shaft, nut and flange. Mark the relative positions of the pinion, nut and flange before removing the nut. Count the number of threads visible between the end of the nut and the end of the pinion shaft and record it for use later. Keep the companion flange from moving while the self-locking pinion nut is loosened. Remove the pinion nut. Withdraw the companion flange. It may be necessary to use a two or three-jaw puller engaged behind the flange to draw it out. Do Not attempt to pry behind the flange or hammer on the end of the pinion shaft. Pry out the old seal and discard it. Lubricate the lips of the new seal with high temperature grease and tap it evenly into position with a seal installation tool or a large socket. Make sure it enters the housing squarely and is tapped into its full depth. Align the mating marks made before disassembly and install the companion flange. If necessary, tighten the pinion nut to draw the flange into place. Do not try to hammer the flange into position. Apply non-hardening sealant to the ends of the splines visible in the center of the flange so oil will be sealed in. Install the washer and pin ion nut. Tighten the nut carefully until the original number of threads are exposed. On semi-floating axles, measure the torque required to rotate the pinion and tighten the nut in small increments until it matches the figure recorded. In order to compensate for the drag of the new oil seal, the nut should be tightened more until the rotational torque of the pinion slightly exceeds what was recorded earlier, but not by more than 5 in-lbs. Connect the driveshaft and lower the vehicle.

Place the vehicle over an inspection pit or raise the rear end to provide adequate working clearance. Disconnect the driveshaft and tie it to the body sideframe. Using a torque wrench, check the torque required to rotate the pinion and record this for use later. Scribe or punch alignment marks on the pinion stem, nut, and flange for reassembly. Count the number of threads visible between the end of the nut and the end of the pinion stem and record for use later. Use a suitable tool to hold the pinion flange still while removing the self-locking pinion nut. Unscrew and remove the pinion nut. Withdraw the companion flange using a two or three-legged extractor if necessary. Pry out the old seal and discard it. Lubricate the lips of a new seal with extreme pressure lithium-based grease and tap it into position. Align the mating marks and install the companion flange, using a spacer if needed. Apply a non-hardening gasket sealer on the ends of the splines in the center of the companion flange. Install the thrust-washer and nut, tightening carefully to expose the original number of threads. Measure the torque required to rotate the pinion and tighten the nut slightly until it matches the recorded figure. To compensate for the new oil seal, further tighten the nut so that the rotational torque of the pinion exceeds the recorded value by 1 to 5 in-lb. Reconnect the driveshaft, install the brake drum and wheel, and lower the vehicle.

To replace the pinion oil seal on a vehicle, first, place the vehicle over an inspection pit or raise the rear end to provide working clearance. Disconnect the driveshaft and tie it to the body sideframe to prevent it from sliding out of the transmission. Use a torque wrench to check the torque required to rotate the pinion and record this for later use. Scribe or dot punch alignment marks on the pinion stem, nut, and flange for proper reassembly. Count the number of threads visible between the nut and pinion stem and record this as well. Use a suitable tool to hold the pinion flange still while removing the self-locking pinion nut. Unscrew and remove the nut, then withdraw the companion flange using a two or three-legged extractor if necessary. Do not attempt to lever behind the deflector or hammer on the pinion stem. Pry out the old seal and discard it. Lubricate the lips of a new seal with lithium-based grease and tap it into position, ensuring it enters the housing squarely and to its full depth. For installation, align the mating marks made earlier and install the companion flange, using a spacer if needed. Apply a non-hardening jointing compound to seal any oil seepage. Install the thrust washer and nut, tightening the nut carefully to expose the original number of threads. Measure the torque required to rotate the pinion and tighten the nut slightly until it matches the recorded figure. To compensate for the new oil seal, further tighten the nut so that the rotational torque of the pinion exceeds the recorded value by 1 to 5 lbs-in. Reconnect the driveshaft, install the brake drum and wheel, and lower the vehicle.

Place the vehicle over an inspection pit or raise the rear end to provide adequate working clearance. Disconnect the driveshaft and tie it to the body sideframe. Using a torque wrench, check the torque required to rotate the pinion and record this for use later. Scribe or dot punch alignment marks on the pinion stem, nut, and flange so that they can be refitted in the same relative position. Count the number of threads visible between the end of the nut and the end of the pinion stem and record for use later. A suitable tool must now be used to hold the pinion flange quite still while the self-locking pinion nut is removed. Unscrew and remove the pinion nut. Withdraw the companion flange using a two or three-legged extractor engaged behind the flange. Pry out the old seal and discard it. Lubricate the lips of a new seal with extreme pressure lithium-based grease and tap it into position. Align the mating marks made before dismantling and install the companion flange. Smear a non-hardening jointing compound on the ends of the splines visible in the center of the companion flange. Install the thrust-washer and nut, but tighten the nut carefully so that the original number of threads is exposed. Measure the torque required to rotate the pinion and tighten the nut fractionally until the figure compares with that recorded before dismantling. In order to compensate for the drag of the new oil seal, the nut should be further tightened so that the rotational torque of the pinion exceeds that recorded before dismantling by between 1 and 5 lbf-in. Reconnect the driveshaft, install the brake drum and wheel, and lower the vehicle.

Use Tool J-8614-10 or an equivalent tool to hold the pinion companion flange.

The pinion nut should be tightened until the original number of threads are exposed. The torque required to rotate the pinion should be measured and the nut should be tightened incrementally until it matches the recorded figure, slightly exceeding it to compensate for the new oil seal.

Use a chain wrench to keep the companion flange from moving while loosening the self-locking pinion nut.

Tap the new seal evenly into position with a seal installation tool or a large socket, ensuring it enters the housing squarely and is tapped into its full depth.

Before removing the pinion nut and companion flange, alignment marks should be made on the pinion shaft, nut, and flange, and the number of threads visible between the nut and shaft should be counted.

The companion flange should be installed by aligning the mating marks and tightening the pinion nut if needed. Non-hardening sealant should be applied to the spline ends on the flange.

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