In my 1997 GMC Yukon K1500, the transfer case is leaking at the seam between the two halves. The T-case is NP241C, I think. It was probably serviced by the previous owner, since I can see red RTV sealant between the case halves. I’d like to reseal it. Do you think it’s possible to split the case and reseal it while it’s still installed in the vehicle? I understand there are 2–3 snap rings on the output shaft that need to be removed, but it looks like there might be enough space to do that with the transfer case still in the truck.
Transfer case leak
- Thread starter santon
- Start date
Indeed it is, but the servicing may require some Specialty Tools and likewise, particular R&R Parts and Seals Kits available from this Vendor. Know that in many cases, some of the internal parts located in close proximity to the internal gears, chain drive and axle shaft(s) over nearly 30 Years of reliable service are capable of employing 'Newton's Third Law of Motion' in counter-valence to the Torque being incessantly present between some of these parts and the Outer Shells from long operation...and literally... Pound their contact surfaces together often enough to finally manage to penetrate through the Shell areas affected... and begin a problematic "Transfer Case Gear Oil Leak" that can be misinterpreted as coming from failing Case PTFE and Rubber Seals.
The cases that may be made of Magnesium are difficult to repair because of the dangerous nature of the metal igniting and burning out of control if any welding is attempted to close up the holes involved in the mistaken belief that they are made out of Aluminum. TIG welding might be possible, but such deserves the careful and expert attentions of Pro Welders and always performed with maximum safety in mind. Think... "Magnesium Fire Starters" as an example and the basis for all this concern
There are kits with updated replacement components meant to prevent further damage from this Counter-Torque Phenomena. Bear this in mind if you decide to eschew a Hands On Tear Down and Rebuild and wind up buying someone else's headache with a like cause and origin of these mysterious "leaks". Due Diligence and more Research is Always a Good Guide to Action.
For the requisite Kits and Tools...
The cases that may be made of Magnesium are difficult to repair because of the dangerous nature of the metal igniting and burning out of control if any welding is attempted to close up the holes involved in the mistaken belief that they are made out of Aluminum. TIG welding might be possible, but such deserves the careful and expert attentions of Pro Welders and always performed with maximum safety in mind. Think... "Magnesium Fire Starters" as an example and the basis for all this concern
There are kits with updated replacement components meant to prevent further damage from this Counter-Torque Phenomena. Bear this in mind if you decide to eschew a Hands On Tear Down and Rebuild and wind up buying someone else's headache with a like cause and origin of these mysterious "leaks". Due Diligence and more Research is Always a Good Guide to Action.
For the requisite Kits and Tools...
NP241 Transfer Case Rebuild Kits, Repair & Replacement Parts Online
Rebuild the transfer case on your GM, Jeep, Dodge & Chevy vehicles with our selection of new process 241 parts. Premium-quality parts at prices that can’t be beat.
www.allstategear.com
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Quick update — I pulled the transfer case, cracked it open, and resealed it. Replaced the dual-lip seal in the adapter too. Prepped for the job with snap ring pliers, Loctite RTV, and some new snap rings, but the originals were actually fine.
Did it all on the ground with a buddy, no lift. Getting the TC back in was a nightmare; that thing is heavy.
I couldn’t get all the old gasket off between the TC and the trans adapter. Tried to scrape the old gasket off, but some old gasket material remained on the surface. Put a new paper gasket between the trans and adapter. I glued the gasket to the TC by RTV but forgot to put RTV on the adapter side.
Now there’s no leak from the TC itself (which is great), but I’m getting a drop of ATF at the lowest bolt where the adapter meets the transmission.
Thinking of removing that bolt, cleaning/drying the hole as best I can, and putting some RTV on the threads before putting it back. Really don’t want to drop the TC again. The leak seems minor - I drove ~30 min, saw one drop. Let it sit for 6–7 hours, no puddle.
What would you guys do? Is there any chance the paper gasket will “settle” with a few heat cycles and the leak will stop? Or should I try tightening the bolts? I think they’re already tight, but I could try loosening them and re-torquing.
Did it all on the ground with a buddy, no lift. Getting the TC back in was a nightmare; that thing is heavy.
I couldn’t get all the old gasket off between the TC and the trans adapter. Tried to scrape the old gasket off, but some old gasket material remained on the surface. Put a new paper gasket between the trans and adapter. I glued the gasket to the TC by RTV but forgot to put RTV on the adapter side.
Now there’s no leak from the TC itself (which is great), but I’m getting a drop of ATF at the lowest bolt where the adapter meets the transmission.
Thinking of removing that bolt, cleaning/drying the hole as best I can, and putting some RTV on the threads before putting it back. Really don’t want to drop the TC again. The leak seems minor - I drove ~30 min, saw one drop. Let it sit for 6–7 hours, no puddle.
What would you guys do? Is there any chance the paper gasket will “settle” with a few heat cycles and the leak will stop? Or should I try tightening the bolts? I think they’re already tight, but I could try loosening them and re-torquing.
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I removed the driveshafts and the crossmember, then completely removed the top and bottom bolts and loosened the remaining four bolts. This allowed me to move the TC back by about 1.5 cm. I let the ATF drip out, then cleaned the surface and the gasket, applied RTV to the adapter surface, reinstalled the bolts, and tightened everything. The leak is fixed.
It seems that RTV is not really needed here - the paper gasket should be sufficient, provided the mating surfaces are completely clean. In my case, there was some old gasket material left on the mating surfaces, so I used RTV to fill the imperfections.
It seems that RTV is not really needed here - the paper gasket should be sufficient, provided the mating surfaces are completely clean. In my case, there was some old gasket material left on the mating surfaces, so I used RTV to fill the imperfections.
