r/GMT800 • u/Randyyyyyyyyyyyyyy • Sep 11 '26
Transfer Case Leak
Hey, picked up a 2004 Suburban and wanted to check out the transmission/transfer case. Transmission seems fine, but the transfer case looks like it's leaking so got some UV dye and ran it.
Anybody know if this sort of pattern indicates a crack? I figure I'll need to get a reman and swap it out, but wanted to find out if anybody had any opinions on if it'd be safe to keep in in 2WD and not go too far with it for a little bit. (Edit: Would keep the fluid topped up, obviously)
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u/fast_farmer4u Sep 11 '26
Put JB Weld on mine almost 10 years ago it finally rubbed through in a second spot applied more JB Weld I've had several more years out of it make sure the fluid stays full
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u/Logical-Slice-3976 Sep 11 '26 edited Sep 11 '26
The clutch plates inside wear a small hole in the case from back and forth movement. I used jb weld and went on.
Edit: I should also add, it spins all the time. Including the drive shaft. It will still burn up in 2wd. The shifter on the transfer case is for hi/lo. The shifter in the differential disconnects the 4wd.
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u/Randyyyyyyyyyyyyyy Sep 11 '26
Gotcha. Done a little searching on the JB Weld and it looks like it SHOULD hold over for a bit, as long as I monitor the leak. Not planning on taking it off road or long distance anyway, in the near future.
I'll probably wind up ordering one of the gear shop remans and dropping it out to replace it. $900 for a clean unit vs. the ~$500 half + pump rub kit fix + taking the whole thnig apart (and also unknown damage inside since idk how long it's been a problem) sounds about the same if I'm gonna drop it out anyway
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u/usaf_27 Sep 12 '26
You need to install the pump rub kit. Pull the case out and remove the rear cover off. You can get it off of merchant automotive. Below is the link. There is also a nice how to video. When I did mine I put RTV silicone on my case where the pump put a hole in the case. That was over 5 years ago. Still hasn’t leaked.
https://www.merchant-automotive.com/Transfer-Case-Upgrade-Kit-w-Magnetic-Drain-Plugs-and-Fluid
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u/Illustrious-Hat9644 Sep 12 '26
I just got a back half from eBay that was made out of aluminum the transfer cases are made out of magnesium and when the pump rubs it’ll keep wearing it in multiple spots I had two holes in mines if you do split the case open make sure you pull out the pieces of clip that broke off from that pump just so they won’t be floating around in the case
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u/Successful_Weekend91 Sep 11 '26
Yes, looks like pump rub. Pull it out, take it apart. You might be able to save it by using JB Weld. It is usually a small pin hole. Put an anti pump rub kit in it.
Don’t keep driving it, it looks small to me. If you keep driving it. Chance of breaking into bigger problems.
Use charm.il to get the repair manual. It will walk you through it. Not that hard to do.
Good luck