Symptoms
ATF dripping from the rear output, a driveline clunk, or a slip yoke pulling out as the suspension droops on a lifted truck. A worn chain can also skip or slap.
The fix, step by step
- Both cases are aluminum, chain-driven and filled with ATF.
- Drain the case, drop both driveshafts and unbolt the case from the transmission adapter.
- Split the halves, check the chain for stretch and the bearings for wear, and replace all seals and gaskets.
- On a lifted NP241, a slip-yoke eliminator gives you a fixed rear yoke and a shorter shaft.
- Offroad Design's kit uses a common 32-spline yoke shortened by 1/4 inch.
- Refill with ATF.
Tools & part numbers
- Transmission jack
- snap-ring pliers
- seal drivers
- RTV
- torque wrench
Where to buy the parts
NP241 and NP208 seal and gasket kitOffroad Design ↗Amazon ↗
NP241 rebuild kit, '88–'93 GMOffroad Design ↗Amazon ↗
GM NP241 slip yoke eliminator kitOffroad Design ↗Amazon ↗
1981–1988 GM NP208 transfer case partsTorque King ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Chevrolet K5 Blazer (1973–1991) parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.