2005 GMC Envoy 4wd problem...any help appreciated

[pshabou]

Vehicle : 2005 GMC Envoy SLT 4.2 4WD 140k

Problem: 2 winters ago, while driving the truck in 4 HI at about 30 mph in the snow, the wheels (I assume front) abruptly locked up and made me spin out into a ditch. When I had the truck pulled out, i touched the gas, and the truck wouldn't move. When I would switch back in 2 wheel drive, truck functioned normally but now with front end noise, again when in 4 hi, nothing but a bunch of crunching noise from the front end.

I have taken it to a couple local shops, I have heard transfer case, 4 wheel disconnect and front differential. Both actuators are functioning properly, no 4wd light is on.

I used the offroadtb flow chart to diagnose the system, and the outcome is the 4 wheel disconnect, could it be all 3? I don't want to spend 4-500 on a 4 wheel disconnect, then another 1k on the differential, followed by another amount on the transfer case.

With all the snow we are getting in detroit, I would love to get the 4 wheel drive in the envoy functioning again.

All help and advice is greatly appreciated. Thanks Guys!

Paul

 

[Playsinsnow]

What's the maintenance history like on the differentials and transfer case? Could be if they were neglected. I bought my ATP disconnect on ebay for $320-350ish shipped from a seller in NY.

 

[The_Roadie]

The differential and the transfer case are prime suspects. Especially if the fluid change intervals weren't followed religiously. 100K for the diff, 50K for the transfer case.

When you took it to the local shops, did ANYBODY bother to check the levels, drain the fluids and check for how much drained out, and/or do a proper service?

The disconnect is virtually incapable of causing wheel lockup, since the sliding collar would break first.

My money's on the diff. Let us know what the fluid change history is on the truck.

 

[pshabou]

The differential and the transfer case are prime suspects. Especially if the fluid change intervals weren't followed religiously. 100K for the diff, 50K for the transfer case.

When you took it to the local shops, did ANYBODY bother to check the levels, drain the fluids and check for how much drained out, and/or do a proper service?

The disconnect is virtually incapable of causing wheel lockup, since the sliding collar would break first.

My money's on the diff. Let us know what the fluid change history is on the truck.

Roadie, thanks for the reply

I purchased the vehicle as a certified GM USED back in 2010. They told me that all the fluids had been flushed and filled, including the oil in the drive train components. I should of taken that with a grain of salt. The car had about 60k miles on it. When the incident happened, I had about 110 thousand miles on it, and over the last 2 years I put on the 30k. I never touched the fluids in the transfer case of front differential.

If the front differential is the culprit, and its so messed up that its causing the lock up, it must be the ring and pinion is physically broken in pieces. I will rip the differential out this weekend, and take it to a local shop who quoted me 350 on the rebuild plus parts. Or I can purchase a used one from the junk for around 400. What do ya think?

While I am at it, I think i'm just going to take the 4 wheel disconnect out, take it apart and clean the internals, check for any wear and tear replace if needed with new grease.

This should be interesting. Thanks for the replies.

Paul

 

[C-ya]

Welcome. Sounds like not so much fun. I know I have enjoyed the 4WD over on this side of the state.

Let me be the first to say that you should change the transfer case fluid two years ago, too. It may not be contributing to your issue now, but it certainly isn't doing the xfer case any favors to have that fluid in there that long. Change interval on the xfer case is 50K miles like Bill mentioned above. The fluid in the diffs (front and rear) may be OK assuming they were really changed. (Doesn't it suck to have to wonder if a dealership actually did what they are supposed to do??) They are probably close enough now that I would change them - or maybe when spring rolls around.

Anyway, I hope you get it sorted out quickly and for not too much scratch.