Help with transefer case popping into neutral

[jbhebert]

I have a '93 GMC 2500 automatic with an NP241 transfer case (manual shift). In the last month or two the transfer case has started popping into neutral. Usually it does this when I go from P to R or D, or if I let off the gas at higher speeds. It has been getting worse to the point where it does it every time I put the transmission in gear. It does it in 2WD or 4WD high, but 4WD low range seems fine. The shifter doesn't seem to be binding and moves smoothly through the ranges, and I do not hear any odd noises when it is in gear to indicate a problem. I was thinking I might just pick up a used transfer case and swap it in, but if anyone has any ideas what might be causing this I'd appreciate it. I have more experience with gear drive cases, so I'm not sure what to look for in a chain drive case.

Thanks.

J.B.

[DSBANHEN]

Sounds like the infamous transfer case snapring in the rear is broken and the gear train in the case is walking around. You may have other damage and not know it yet. Get set for a teardn!! DB

[jbhebert]

Infamous, huh? I didn't come across that one in my searches; I was thinking it was either a bent fork or the wear pads on the mode and/or range selectors needing replacement. I guess I'll just have to pull it and see what I can find.

Thanks.

J.B.

[trannyboy]

sounds like broken snap ring. if you have been running it like this for a while find another transfer case for donor parts.before you buy an extra case grab hold of the output shaft and make sure that it does not have excessive in and out play.there is a company that makes a retainer for the snap rings forget who but it is in last months peterson magazine.i usually just go to the local auto parts store and go through there snap ring selection till i find one that fits good and has is thicker than the stock one.

[Shaker]

yep the snap ring...internal guts are 'walking' in case.....

[orangefj45]

very common problem on the 241s. the snaprings always let go.

there's a company called sonnax that makes an aftermarket setup for this case and cures the problem for good.

http://www.transmissionspecialty.com...100420-01K.htm

i've installed a few of these, they work really well. simple fix that can be done in the vehicle in about an hour, no need to pull the t-case. good luck.

[Blackchevy]

I just replaced my snap ring w/ the collar( the one featured in 4wheel) from Gillys! Took less than an hour and wasn't very expensive! Looks like a solid piece too! I have a couple of pics if anyone is interested!

[jbhebert]

Thanks for the info. I don't drive the truck a lot, so hopefully I didn't do too much damage. I'll pull it apart and see what it looks like and if need be I'll track down another case. Is it worth doing a complete rebuld with chain while I'm in there, or just do the snap ring and wear pads?