**Updated with cause (transfer case)...So I'm buying a '00 ECSB 4WD 1500 from a guy at work for cheap because the rear locked while he was going down the road at 60. Its got 195K miles and runs fine. He thinks it might be the transfer case because he found a leak there. I've done the wear plate in the case of our '02 Tahoe to fix the leak a couple years ago. My question is if he ran the transfer case dry would it potentially lock up just the rear end? I was thinking that if the chain broke or a bearing in there froze up that it would lock up the front and rear but maybe just the rear? He pulled the rear driveshaft and the diff would turn freely so I don't think its the rear end.

 

It's more than likely in the rear diff, more specifically, the spider gears in the differential. Same thing happened to my buddies 99 and my 2500HD.

I'd pull the rear diff cover and you should see metal pieces and shavings. If not, it doesn't hurt to look it over and fill it with new fluid.

 

It's hard to say for sure. Just because he was able to turn the rear end freely after removing the drive shaft doesn't mean there is no internal damage inside the rear end.

If it was the rear that locked up it could have taken the Transfer case with it. So as mentioned it wouldn't hurt to open it up and look.

Sounds like either way the Transfer case has to come out and be repaired.

I would recommend a good visual inspection first before you buy it. The 4L60E doesn't like to be locked up like that. They have been known to explode. This will ensure that your Repair cost are not going to get out of hand based on whatever the vehicle would be worth in running driving condition.

 

Thanks guys. It's actually a Z71 and he's only asking for $1K. I think in running condition its worth at least $3K in the condition its in so I could throw $2K in parts at it (not including my time) before I get near upside down on it. I'll open up the rear and the transfer case to see how they look. I'm picking it up tomorrow.

 

These tcases are very strong, youll see when you open it up. Even if the chain broke, 2wd will still work fine. Theres not much in there to break, the shaft would probably be the most likely and its pretty stout.

 

You can't go wrong at that Price. Not sure about your area or what shape the truck is in overall but I would think it would be worth a little more even with the higher milage. Unless it's on the rusty side of course.

Keep us posted on what you find.

 

Ok - I've got in in the driveway now. Pushing it with the rear driveshaft out it started giving some resistance and almost sounded like a playing card stuck in a bicycle wheel when we were pushing it if that makes sense. Something was making some noise either the case or the tranny when pushing it around and its not the rear end. Another downside is it has major flat spots on the rear tires from where he came to a quick stop going 60 down the road. Too bad considering the tires have a lot of tread on them. I'll post up once I take the transfer case off...its definitely leaking fluid from the case/trans area.

 

Curious to see what you find. Sounds like something in the T case.

 

Pulled the transfer case today. I started it up and put it in drive to see if the trans output shaft would turn and it was spinning freely and throwing trans fluid everywhere (which I should've expected). I also scared myself for a minute when it would grind when I put it back in park. Then I realized its because the trans is spinning when I put it in park (no way to stop the trans with the driveshafts out except to turn the truck off in drive which I didn't think about)...whoops. So the fact that both diffs turn with the truck on the ground and driveshafts out plus the trans seems to spin freely with the transfer case out makes me think its the transfer case without splitting the case to see what's inside. What do you guys think?

 

Ok so it was definitely the t-case. I put a used one in today and was able to drive it around without any issues (other than the flat spots on the rear tires creating a nice and bumpy ride). The only issue I now have is I can't get the damn electric actuator to lineup with the shaft on the t-case. I tried letting the actuator hang there and shift it from 2WD to 4WD to see if it would align itself correctly prior to bolting it on but no luck. So I'm driving it around with the front driveshaft out until I can get another encoder/actuator. My theory is that when the transfer case locked up it caused that shaft to turn slightly (without the actuator energized) and forced it into a weird position which its now stuck in. I may try taking it apart and moving it a tooth or two to try and get it back inline otherwise its another $100 for a used actuator. So to date I've got about $1550 in the truck including the purchase price, used t-case, gaskets, trans filter, and fluids...not too bad.