1988 F150 4x4 transfer case

Hopefully someone can help with this question. I have a 1988 F150 that I had to shift to 4-low to back out of an icy driveway. I backed out, pulled back in, aproximatly 200ft total. A few days later I went to move it again. I first shifted it back to 2Hi and then backed out of the driveway. It acts like it is still in low range even with the 4x4 manual selector in 2Hi or even 4Hi. Now it wont even engage the front wheels, and yes they are locked in. It has a Borg-Werner 13-56 transfer case. The oil level seems to be fine but it does look a little black. Has anyone had the similar problem or has had problems with their transfer case. If so what is an approximate cost to rebuild it.

Thanks,
Tom

I Had the same problem with my 88 Bronco, but my transfer case locked up, so I ended up pricing a rebuild kit and it would've costed me about 320.00$ and alot of time, what I did is found an awesome deal at junkyard. I got a BorgWarner 1356, with a slip yolk for $300.00, I'd try finding somthing like that first, it was easy as fuck to put in, good luck. Oh, yea, make sure if you do get a used one to flush the shit out of it and put new fluid in of course, royal purple.