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Discussion Starter #1
Hello all, I recently visited a local auto repair shop to get my transfer case serviced on my 96 silverado. They ended up replacing the transfer case with a used one off a 97 yukon with 91,000 miles. They also replaced the inner seal, front u joints, rear u joint and a couple other exhaust parts. I finally got the truck back, and after a couple days of driving, there is a brown fluid (kinda looks like gear oil?) dripping from the skid plate below the transfer case. When I get my head under there, the fluid is on the underbody of the truck (small patch in one area) on the right upper side of the transfer case and on almost all the frame bars where the skid plate is attached too. The transfer case seems clean along the drain plug and fill plug, but the fluid seems heavier between where the case and the tranny pan are close to each other. (I hope Im right on the placement) Has anybody every seen this? I guess im asking as in could it be possible the transfer case is filled with gear lube and not the correct transfer fluid?
 

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Its possible the shop over filled it or they pulled one over on you and didn't rebuild it and just slapped it in. Sounds like a seal or gasket is leaking. Another thing it could be is gaa from one of the u-joints
 

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Is it a manual or electronic transfer case? If its electronic then it should have ATF for fluid and it shouldn't be brown. If its a manual case then it takes gear lube. Sounds to me like they didn't replace the seals at all or not correctly:grrrrrr:
 

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Discussion Starter #4
Its a electronic transfer case, or at least it should be as to what he claimed was put in it. Idk if the seals were changed on the used one, im guessing they were not. What seal(s) would we be referring to by chance? Just so I could pop my head back under and sorta determine or rule out? :/
 

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Well if its a electronic case then your fluid shouldn't be brown, it should be red like new ATF fluid. Theres seals where the shafts come out of the case and a seal around the case where the two piece case housings are joined together. I would start with the fluid, sounds like they put gear lube in. I've seen this done many times.
 

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Yeah, my father in law mentioned they could have put gear lube in it, I showed him what was dripping and both him and myself couldnt seeing it being atf fluid, its way to dark and almost a oil base. I was thinking of draining whatever was in the case, but im curious, if i change the fluid, wont it leak again but this time with atf fluid?
 

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Well I woud drain it and fill with ATF, drive some and drain again and refill with ATF and keep doing this until you get all the gear lube out and have clean looking ATF. Drive it some and then check for leaks. The ATF has chemicals that help the seals to seal and maybe this is your problem.
 

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Ohh, I never thought about ATF helping the seals seal, makes sense though. Ill have to stop at a dealer tommorow and pick up some ATF fluid. Thanks for your help! Ill let you know what happens with trying what you suggested.
 

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Good luck!!
 

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It could just be lack of attention to detail. Meaning that when they filled filled it they spilled some on the under carriage of the truck and didn't clean it up. Still doesn't change the fact that they may have used the wrong fluid.
 
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