How to Replace the Rear Transfer Case Tailshaft Seal on a Full-Size Chevy Blazer, Chevy Truck, GMC Jimmy or GMC Truck

Video Summary

1A Auto shows you how to repair, fix, change or replace a rear transmission transfer case seal. This video is applicable to full-size Chevy Blazer, Chevy Truck, GMC Jimmy Or GMC Truck models. You will first learn how to remove your existing transfer case tailshaft seal, and then install a new replacement.

Tools Needed:

  • 3/8-1/2 inch Wrench
  • Hammer or Rubber Mallet
  • Flat Blade Screwdriver
  • Torque Wrench

Repair Steps:

  1. Remove driveshaft by removing four bolts at the rear and using a large screwdriver to pry it out. This is easiest with vehicle in gear. Use a screwdriver to mark one side of driveshaft and rear-end so they can be lined up when reinstalling.
  2. With a catch pan underneath pull the front of the driveshaft out of the transmission.
  3. Remove transfer case tailshaft seal using a flat blade screwdriver and hammer to pry it out. Be careful to not damage the transfer case tailshaft. Wipe out the transfer case seal seat with paper towels.
  4. Gently tap new transfer case seal replacement way into place using hammer or rubber mallet. Place a 2x4 with a 1-1 1/2 inch diameter hole cut out over the transfer case seal and use hammer on wood to push the seal all the way in. This makeshift "tool" will distribute the hammer's force more evenly over the tailshaft seal.
  5. Insert front of driveshaft into transmission making sure that mark on rear of driveshaft is on the same side as mark on the rear-end. You may need to use a rubber mallet to get the driveshaft past a certain point, after that it should slide in.
  6. Line up and install driveshaft into rear-end. Re-install the four bolts and torque them to 20 ft-lb.
  7. Refill transmission fluid according to manufacturer's guidelines.

That is how to replace a transfer case tailshaft seal on full-size Chevy Blazer, Chevy Truck, GMC Jimmy Or GMC Truck models. Thanks for watching!

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