4WD trouble?

halfaday · February 1, 2013

Hey guys (and girls )!

Had a little trouble this morning. Put it in 4WD and it felt like the front wheels were gripping and then not gripping off and on. It was still getting me through the snow, but I could feel it going in and out the whole time. When I got to a cleared road, I hit the 2WD button. It still felt like the fronts were still engaged for about a quarter mile and then a clunk! Not a metal clunk, but more like I hit a hole in the pavement. Drives fine in 2WD.

2002 2500HD, CC, long bed, 8.1, Allison tranny, auto transfer case, 150K on the clock.

Thoughts on what to check?

00Silverado4x4 · February 1, 2013

Did you by chance have it in Auto 4wd? That would leave with a feeling of cutting in and out. Your "clunk" sounds like what mine has always done when switching out of 4wd, even if it was in Auto 4wd and 4wd was engaged at the moment of swithcing back to 2wd.

halfaday · February 1, 2013

I don't think my setup is auto 4WD though. By saying that, I mean that there are only 3 buttons: 2hi, 4hi and 4lo.

I've owned the truck since '03 and I have not had this happen before this morning.

Usually I just press 4hi, and it would just engage (pretty much silently). going back into 2hi never produced any clunking before

00Silverado4x4 · February 1, 2013

How's your fluid condition and level? Possibly low, metal chunks being flung around? Left field guess but check the U-joints on the front shaft? I'm not an expert so I'm only throwing out guesses. Sorry if I'm not helping.

halfaday · February 1, 2013

I appreciate your feedback!

Will certainly check all the above. If I find anything "interesting", I'll post my results.

gmtech4 · February 3, 2013

with the powertrain loaded and in 4WD ,you hitting 2wd will do nothing untill the driveline is unloaded,,,by stopping and going to neutral with the tranny,,,,,the driveline will sort its self out and off ya go in 2wd !!!

halfaday · February 5, 2013

Yeah, I have never been a fan of push-button 4WD. If I get her stopped and into neutral, it'll pop out with no trouble. My concern was that something obviously has changed since I was always able to go in and out of 4WD while on the fly. This is new this season. I still haven't had time to get under it yet to check the items that 06SierraZ71 suggested. Too cold! Hopefully this weekend.