Symptoms
4WD light on but no drive to the front, or the front won't disengage.
The fix, step by step
- Bob Is The Oil Guy owners say the front 4WD actuator is known to seize in rust-prone areas and that it's usually a DIY fix.
- Unbolt the actuator, clean and lubricate the shift fork and sleeve, check the vacuum or electrical supply, and refit.
- On trucks with locking hubs, service the hubs at the same time.
- Some owners convert to manual locking hubs.
Tools & part numbers
- Socket set
- penetrating oil
- grease
- multimeter or vacuum gauge.
Where to buy the parts
Locking hub, 1998 TrooperRockAuto ↗Amazon ↗
Front gear oilRockAuto ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Isuzu Trooper (second 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.