My 2002 GMC Sierra Ext cab 1500 4X4 pickup had a major whine when in 4 wheel drive at about 50 MPH. Checked all lube levels and had extreme amount of metal sahvings in front differential. I purchased another and went ahead and swapped them out. When changing them I noticed i could not turn front axle driveshaft even when transfer case is in neutral. I continued the swap and got truck back on road. Disassembled front differential and found ring gear carrier side bearing had failed.Ring and pinion and bearings all shot. Still have whine at 50Mph but is smoother. Questions. Is transfer case supposed to fully unlock front driveshaft in
IIRC the autotrack box always spins the front shaft. why were you doing 50 in 4wd anyways?
Doing 50 due to 6 inches snow covered highway. Not unusual around here in Vermont. Tell me about this autotrack box. So you are saying the transfer case only shifts from high to low? It does not release for 2 wheel drive? Thanks Rick
Was this a brand new unit, or a wrecking yard unit? If you put a used one back in, it's highly likely that it's not much better then the one you took out.
The auto t/cases do not fully disengage the front drive shaft, even when in two wheel drive. The clutch pack is designed to apply about 5% torque to the front driveshaft at all tiimes. If you pick 4hi, you get 100% torque, if you pick Auto4hi, you get between 5% and 100% depending on what the transfer case determines you need....based on available traction. The side bearing failure is basically an epidemic on these trucks, we are fixing/overhauling front diffs on these trucks all the time. It's always one of the side bearings that goes south.
Again, if you installed a used front axle, it may be on the way out too. If you have the same problem again, the real solution is a quality rebuild by someone who knows what the hell they are doing and can set the front diff bearing preloads and gear set up properly. Don't be surprised if you lose your 4x4 in the near future. The front diff problems tend to trash the clutch pack in the automatic t/cases. If you notice any signs of slipping in 4x4....check your t/case fluid...in fact, check it now. It should be a nice blue color.....if it happens to be dark blue or black.....I would suggest that you get the clutch pack overhauled right away. If you catch this early, all you need to do is to overhaul the clutch pack, and install new fluid. If you let it go, it will eventually destroy the transfer case.
don't the plows work in VT? I very rarely have to go through any deep snow (other than the 1/4 mile to the main rd.) and I'm only a few hours east in Maine.
Ian can (and does a few messages down) explain it better than I can.
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