1978 chevy k20

[jimb 8n]

I'm having trouble with my transfer case in my truck. It seems to slip in 4 lock when stuck in snow. Just wanted to find out what may be the reason why this happens.

 

[jimb 8n]

I guess I should tell you it is a full time with a np 203 transfer case.

 

[wsmm]

What do you mean, it seems to slip when in four wheel drive. You do know that unless you're in 4 lock, or 4 part dive the transfer case also acts as an open differential.

 

[R Pope]

NP203 is a chain drive case. When they wear, the chain jumps. Fix it before it self-destructs.