transfercase clunking np203

[zooman jones]

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

[LONGHAIR]

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?

The chain is probably loose, but it really depends upon how low the conversion kit has been in there. The sooner that they are converted, the less wear they get.
With the conversion kit, the chain doesn't turn, or carry any load. Most of the NP203 failures that I have seen were related to the "ring" gear that mounts to the central "spider" shaft. It is a fairly thin stamped piece that won't take much abuse. There is also a torrington bearing behind this center unit. If this fails, it changes the spacing/engagement of other parts.
I wouldn't drive it.....
I wouldn't even try to change the chain with the case still in the truck, but I wouldn't bet that it is your real problem.

[zooman jones]

Ok thanks, so if i am reading you right my best bet is to pull the case and rebuild it? Can I do this my self? I have a factory manual and is there a good book or web site that explains how to do this?

My part-time kit has been in for quite a while. I bought the case use 7 or 8 years ago and the kit was already in it.

Matt