My 94 3500 1 ton dually 5 speed 4x4 transfer case is popping under a load. This happens in 4HI or 4LO but not in 2WD. I put a posi-lok on the front differential thinking that was the issue but I get positive lock on the axle & the transfer case still pops under throttle off the line. If I coast to a stop & re-apply power, it pops again. Feels like a spline is worn or broke or a bushing is weak IMO. The tranny & case are bolted together & look like they can be dropped out rather easily for service. My question is, are they easy to service or should I simply just look for a replacement? Any ideas here? Im not educated on transmissions or transfer cases so any ideas of what to look for would be appreciated. Thanks!

 

It might just be the chain. look in the FAQ/DIY section and download the free FSM for your year.

 

i also had some snaps and pops when in 4wd and then some other mysterious snaps when shifting from reverse to drive.

i removed the tail housing hoping to find a broken snap ring and an easy fix, but it was fine. while looking at it and rotating the rear shaft back and forth - it felt like it had way too much play in something other than the chain, and it also had a clacking sound.

i'd had enough of the noises and didn't want to tear it apart. i also didn't think i knew enough to tell the difference in a good component and a worn out component, so i just ordered a rebuilt unit.

the swap is easy. 2-3 hours (i'm slow) to remove drive shafts, disconnect shifter, vac hose, loosen cross member, 6 nuts, and its out. reinstall is the reverse and you're done.

i got a 231 for the 1500 here for $700 + 100 shipping both ways.
it worked perfect, had no play, no clacking or snapping.
they may or may not have a unit in stock and ready to ship. i got lucky and they did. i ordered on friday and ups delivered it on monday.
http://www.transfercases.com/

 

It's probably the snap ring, as dhvaughan said. That's what it sounds like to me...

 

If it was the snap ring it would be popping in 2wd IMO/IME.

 

Mine didn't do that, but either way it is easy to check.

 

My 98 did, and there was nothing wrong with the snap ring.

 

The popping noise does kinda sound like a chain binding somehow. I drove it to work today in the storm & it did fine outside of the noise. Seems like as long as I have a constant pull on the transfer case its fine & doesnt pop. When I slow to a stop, coast, or gear brake down thats when it acts up. Almost like theres slack in the chain & its slipping a little. Havent opened it up yet & probably wont until the funds allow. Is there an adjustment on the chain or would it just need replaced like a timing chain does when it stretches out?

 

No adjustment that I am aware of. Replacing it wouldn't be a bad idea though. I am sure they stretch just like the timing chain. Granted, it is a meaner chain, but, it is under a lot more stress too.

 

It still would not hurt to at least pull the tail shaft and check the ring. If it is that, fixing it now will be cheaper than what's going to happen if you let it go.