Symptoms
The transfer case jumps out of 2-High or won't fully engage 4-High. On a 1967 800, an IHPA forum member found the shift-cover opening was too small for the levers to travel fully, so check that before you strip the case.
The fix, step by step
- Drain the oil first.
- Support the engine and transmission with a second jack or blocks, and disconnect both prop shafts at the output flanges.
- The case weighs about 70 lb.
- An IHPA moderator recommends a full rebuild with a master overhaul kit rather than band-aid fixes.
- The service manual lists bent forks, a bad spring or bearings as possible causes.
- Refill with SAE 90 GL-1 mineral oil, or straight 50-weight motor oil as a substitute, and not 80W-90 GL-5.
- Early Scout 80s and 800s use the Dana 18, so order the right kit.
Tools & part numbers
- Transmission jack or a second floor jack
- puller
- snap-ring pliers
- seal drivers
- gasket scraper.
Where to buy the parts
Master overhaul kit, Dana 20 transfer case (1966–80 Scout)IH Parts America ↗Amazon ↗
Dana 20 transfer case gasket and seal kitIH Parts America ↗Amazon ↗
Scout Dana 20 transfer case bearing and seal kitSuper Scout Specialists ↗Amazon ↗
Rebuilt Dana 18, 20 or 300 transfer case for Scout 80/800/IIIH Parts America ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for International Scout 80 / 800 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.