Hey guys I could use some help. I have a 88 full size Jimmy and I lost my reverse. I still all forward gears and she moves just fine,there is a some type of whine to it though. I did put it inot 4 wheel and it went fine until I tried to put it back into 2hi and then I heard some grinding.But my cousin tried it about an hour later it worked fine..So my ? is could the transfer case be bad or would it be my tranny..The tranny is a 700R4. Any help would be great. Getting tired of seeing it sit out on the street and not in the dirt somewhere...Thanks again  

sorry pal i cant help you. i dont know much about automatics. theres some guys on here that are very knowledgable though and they will be by soon to help.  

a whine can be from a plugged filter, after sitting the crap falls off of the filter then it moves some more untill its all plugged up again, DO NOT drive it like that, It'll ruin friction steals among other things, that may not need to be replaced otherwise,

Pull off the tranny pan and check for debris, a small amount of metalic flake is normal, a whole pile of black goo and metal however is bad. if it is at a normal level and no burned smell install a new filter and pan gasket, chances are with reverse gone the frictions are burned and the remenants are in the pan and plugged filter.

the t-case is pretty durable if it has been taken care of and not hammered on,  

This is a Tcase issue. The grinding is the give away here. Either the detent in Tcase is woen or the linkage is out of adjustment. When it gets like this when reverse torque is applied it pops out of engagement and grinds.  

also when the chain in t-case is slippin  

didn't catch the grinding part, till now so like the snoman says....  

hey guys thanks for the quick response..I thought that it would probably be the TCase,but wasn't to sure. Not that real mechancially incline with the 4x4s. So I'll go ahead and check that out..By the way have a safe and Happy New Year..  

chopperfreak2k1:
also when the chain in t-case is slippin

Not likely here. When they slip/jump tooth it sounds like it is coming apart down there big time.