The Stovebolt Site Forums The Shop Area General Truck Talk transfer case? or huvs

i consulted my transmission guy via telephone regarding this problem im havin with my transfer case it is a chevy full time 4 wheel drive transfer case with some sort of lock feature or so it says on the knob says 4 hi loc 4 low loc
so heres my problem while 4 wheelin yesterday it didnt have 4 wheel drive i locked in the hubs and nuthin just the rear tires went i could put it in 4 low and the transfer case seemed to be working at least for the rear tires but no go in the front i crawled under the truck while it was in park and tried to turn the drive shafts the front shaft turned by hand when i had the hubs unlocked my question is wouldnt the truck not drive if the transfer case was bad?

My old '77 GMC Jimmy had the NP203 transfer case that was like that. If you have locking hubs then it has been converted. The neat thing about that transfer case (NP 203) is that you can have 2WD HI and 2wd LO. Not that I cared about that but it's just cool to know.
Sounds like something isnt jiving in the transfer case. If what you have is the NP 203 then it is worth fixing. Although it is not the gear drive NP 205 it is still a very strong case.
Check with the folks at http://coloradok5.com/
Those guys know everything that there is to know about this subject. Sorry that I couldnt be of more help - it's been a while since I had that GMC Jimmy.

There is a differential gear set in the NP 203. This is what allows it operate as a full time system. When the shift lever is in the Loc position, it locks this differential so that power is positively delivered to both axles. You may have something wrong with this center differential, or it may be a problem with the chain that provides power for the front axle.

If you have manual locking hubs and the truck moves when the hubs are unlocked then it has a part time kit in it and there is no longer a diff in the case.

Unless you are hearing some horable noises than the problem is probubly the shift linkage. They used an overly complicated box that has a bunch of springs and cams in it to make one handle move 2 links in the correct order. None of the 3 trucks I have had with 203's in them have had a non-working box. The best solution is to gut the box and put in a pair of shifters to work the linkages. You can usualy force the shifter to stay in gear by holding it forward or back.

Also check your floor clearance and make sure the lever isn't bottoming out on the floorpan.

thanx for the info guys ill try some stuff with it i know i dont wanna pull that baby out again it took 5 grown men to put that sucker in there man its a heavy case