Towing a 7500# 5th wheel trailer, with '01, 2500, ext. cab, longbox, 4X4, 6speed, dana 80 rear, 220k. About 65mph, in very cold weather, around -10F. Left rear locked up tight, skidded to stop. After sitting there about 15 min, assuming somthing went out in rearend, put in 4wheel drive and drove up to truck stop about a mile away (cop told me to move it or he had to call a tow truck). Drove about 7 or 8 mph in 4wheel drive the mile or so to truck stop with lots of crunching and grinding going on underneath, sound coming from the rear I'm about 99% sure, I know driveline noises can travel. Friends picked me up and trailered the truck home. Waited a couple of days, looked at diff (open diff), ring and pinon, outter bearing, breaks, Nothing seems to be wrong, can't find the problem, took it for a couple of short drives and it seems to be fine. I'm scared to take for a long drive or try towing or hauling to see if that will show the problem with the potential of having an accident if it locks up again.
Any Ideas Anyone? Could something in the trans or transfer cause only one wheel to lock? Could a bearing cause the LR tire to lock and then seem fine once it cooled and had less of a load on it? Could the break cause all this? Any help. Thanks.

 

Check the rotor to see if there is any damage to it from possibly something getting caught between the rotor and the caliper

 

Drum breaks, i had already checked them for signs of a rock or something getting caught in there but didn't see anything. Thanks for the thought anyway.

 

I suggest that you pull the left axle and hub and check for bearing damage just to be sure. Can't think of why the left rear brakes would lock up the wheel with all the noise you describe.

 

wheelbearings or breaks possibly...luckily if i remember u can buy wheel bearings by themselves for the rear...no need to buy the whole hub