transfercase clunking np203

[zooman]

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Hey guys I had my 78 chevy out today with the np203 part-time kit. I noticed when in park I could here a clunking noise coming from the transfercase. I put the truck in 4 wheel drive and put it reverse and it didn't really want to move. I had to give it some good throttle to move.

Do you guys think my chain is toast? I put it in 2 wheel drive and I could still here the clunking but it would move in reverse no problem. Is it still safe to drive in 2 wheel or should I just park it for now?

Is it possible to change the chain with transfercase still in the truck?

Thanks guys
Matt

[DnStClr]

It sounds like the chain is gone doesn't it? The clunk might be from the chain being stretched. If it's hitting the housing it could blow a hole in the housing since it's only aluminum. I don't think you can put a new chain in without taking the box out. The chain is at the rear of the case. and you'd certainly want new seals installed with a new chain. Call the transmission shop and see what they charge. It might be less than $400.   

[Fordeatinz71]

a 203 has a cast-iron case.  that's why it's so heavy.  the NP208 was GM's first aluminum-cased t-case.  you can't replace the t-case chain with it in the truck...you have to split the case to do it and while you're in there it's dumb not to simply rebuild it...are you positive it's the t-case clunking and not the transmission?

[zooman]

I am pretty sure its the transfercase but I could never be positive.

Yesterday I moved the truck back and fourth and there would be no clunking and everything was fine.  I put it in 4 wheel drive and when I would go in reverse it was like the truck was slipping.  It would be fine in drive but in reverse I would have to rev the truck up to go backwards. 

I am guessing its the chain slippping.

Am I right?

Thanks
Matt