Symptoms
Hubs that won't lock in 4WD, grind or clunk when they engage, or won't release.
The fix, step by step
- Jack up one front wheel at a time.
- Remove the hub cover bolts and pull the hub body, then clean out old grease and water, check the internals for wear and broken parts and regrease lightly.
- While it's open, check the wheel-bearing preload and the axle shaft splines.
- If an auto hub is worn out, many owners fit a pair of manual hubs.
- Test 4WD high and low on loose ground afterwards.
Tools & part numbers
- Hex keys or sockets
- snap-ring pliers
- grease
- factory manual for bearing preload.
Where to buy the parts
Locking hub, 1990 TrooperRockAuto ↗Amazon ↗
Wheel sealRockAuto ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Isuzu Trooper (first generation) 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.