1999 2500 HD transfer case leaking

[gtwitch]

After taking the transfer case out twice and tear down/clean and reassemble with sealant on the mating case halves, It appears that it still leaks from where the case halves mate, I don't know if there is something that i am missing, i used ultra black peramatex silicon on clean surfaces and still leaking after the first 600 miles or so. I would appreciate any input here, and I'm not new to auto/truck repair and it has me pulling my grey hairs!

 

[NIsaacs]

Do you let it cure overnight before adding fluid? I have found on my Dana front/rear covers, if I don't, I will get a messy seep.

 

[Topzide]

@NIsaacs, That's the same thing that I was thinking. In some cases, you need to let sit a few minutes to skin cure before placing together to avoid leaking. Have had issues on small engine repairs on filling to soon after putting parts back together. The baddest stuff that I've used in the past was Toyota's FIPG black sealer (Fix In Place Gasket). The extreme black rtv is close. All depends on the use and fluids that it needs to hold back. Sounds like it has to come back out, clean and wipe down and start over. Maybe use some acetone for the final wipe down if not done the first time. Have had some brake cleaner cause a residue to be left on parts. Good luck with the repairs and know you're not the first one to have an issue with a repair!

 

[gtwitch]

Thanks for the suggestions here. In my last winter projects, I was building a couple of 175 HP 2 stroke snowmobile engines and Indy Specialties who did the crankshafts and other work for me before I re assembled suggested Permatex "The Right Stuff" for sealing the engine crankcase halves (pressures inside the crankcase probably 75 to 125 psi pulsating) and also was told to let the sealed crankcases sit at least 24 hrs for the cure. 15 years ago I used a produce called Yamahabond which I never had leak. Thanks again!!
gtwitch in wyoming

 

[BigPapa]

Yamabond 3 & 4 is good stuff.

 

[Ozymandias]

On case halves like this I always put (after degreasing) just a thin layer of RTV on both sides, with my bare finger. Rub it onto the sealing surface, then wait 2 minutes, then put it together.
Never had a leak by doing so.
Most people put way to much of sealant on, it needs so tiny little only to cover/fill the imperfections of the mating surfaces. There is no gap filling needed.

 

[Signal73]

Man I hope I don’t get blackballed for posting this link, but if ford got one thing right it’s this silicone sealant.

https://www.motorcraft.com/us/en_us...lers-and-adhesives/rtv-silicone-sealants.html

 

[Cummins12V98]

"The Right stuff" I never waited to add fluid on my Dana 60/70's. Bead all around, snug the cover up and add fluid, never a leak.

 

[Topzide]

What it all comes down to is prep! Spend the extra time doing the prep and the finished project will come out way better than expected! This seems to apply to just about anything that you have to do. Have had a difficult time teaching the DW this! When she is working on a wood project, I keep telling her to keep sanding and get that "look"! She's made the comment to me that the projects I've done have a mirror finish. I was taught that when you think you're done, change grit and keep sanding! I'm a bit "anal" on how clean I make things before putting back together! I just don't like to have to pull back apart and reseal and reinstall! Take the extra time and you'll have much better results in whatever you're working on!