My Friend just bought a 1990 F350 diesel single rear wheel pick-up and he is having trouble with his transfer case. it runs and drives in 2-wheel drive but when he puts it in 4-high the front axle doesn't engage. But when he puts it in 4-low the front axle engages it doesn't make sense. But I think the Transfer case is a Borg-Warner 13-56. But im not sure. If you have any ideas or you know what it is then please drop me a line.

Thanks for the Help.  

Same "clutch" is used for front axle 4hi or 4lo in Tcase.  

What makes you think it's not engaging? It ought to be physically impossible to engage the front axle in 4Lo but not in 4Hi.  

The lever moves into four high and low but the front wheels dont turn when placed in four high.  

Dirty_Dog:
What makes you think it's not engaging? It ought to be physically impossible to engage the front axle in 4Lo but not in 4Hi.

Not really if you really knew your Tcases. Some models of manually shifted Borg Warner Tcases use a electromagnetic coil to engage the dog clutch to drive front axle. If it is one of those it could be a linkage/switch issue.