All 4 wheels locked up (froze) in 4wheel drive

[letsgo]

My son inlaw went into 4 wheel low drove 50' in snow, heard some grinding, then all 4 wheels locked up, thus skiding to a stop, wheels would not turn. There is nothing in 4 wheel high, the engine revs, but truck doesnt move, in 2 wheel drive every thing works, truck is at the dealers taking a christmas break (pun intended), but their so called 2 hour diagnostic didnt reveal anything.

any thoughts as to the problem???

And a merry Christmas to all.

[DmaxMaverick]

....but their so called 2 hour diagnostic didnt reveal anything. Weren't they able to reproduce the problem? Seems to me that stuck is stuck, codes or no codes. They probably just hooked up the Tech II and said, "No codes. Nothing wrong here. Gotta' get to Granny's house for Christmas. Yuk, yuk."

The problem would seem pretty straight. Because it didn't engage anything in 4 hi, you can rule out anything after the transfer case. If it drives normal in 2 hi, rule out the tranny. That pretty much leaves one thing. Transfer case. Sure looks like a "no brainer" to me, which may be appropriate for your dealer.

Push button or stick? Could be an encoder motor problem in the transfer case if it's push button. With the grinding noise, the problem probably didn't stop there.

Good luck, and Merry Christmas!

[dmaxalliTech]

Sounds like the transfer case to me.. broken chain or...

[letsgo]

Thanks for the replies.

Will report findings hopefully by wednesday.

[letsgo]

Well it turns out to be the front differential, they are in the process of deciding what has to be replaced, will report final damages when the truck is returned.

drive safe.

[letsgo]

The front axil is being replaced, no word as to what happened inside the differential.

Thanks and drive safe.

[DmaxMaverick]

I haven't seen your truck, so I'm going out on a limb here.

I'm not convinced your dealer has diagnosed the problem.

I don't understand how a front diff problem could cause:
....There is nothing in 4 wheel high, the engine revs, but truck doesnt move, in 2 wheel drive every thing works....If it is the front diff, it surely wouldn't go into a "neutral" state when in 4 hi, lock up in 4 lo, and work "normal" in 2 hi.


There may be something wrong with the front diff, but I don't think it is causing the problem you originally stated. Sounds like your dealer is throwing parts at it.


dmaxalliTech

What do you think? Is there more to this [electronic] 4 wd operation than we know about? Doesn't make sense to me.

[letsgo]

Truck returned Thursday, the work order stated that the differential pinion was siezed that the bearings were frozen and all bearing surfaces scored (6000 miles on truck), the oil level was normal and no signs of oil leaks, this truck was maintained by only one dealer, I think some one forgot to put oil in the differential.

The dealers in the Toronto area and most of Southern Ontario have pickups that visit GM parts depot twice a day, and a one day delivery from Michigan (at least that is where the diff. was supposed to come from).

drive safe.

[Cliffee]

I think I'll go check my levels!!!