NP241C issues

[blue_ls10]

Hello all,
This is my first post here, but I’ve been lurking for a little while since I picked up my project ‘79 K25.

Quick background on it, but I bought it from a kid who burned up the transmission in it (TH350). With no luck finding a replacement Th350 or 400, I found a 700R4 NP241C passenger drop combo. Transmission seems solid, had clean fluid for what was left in it. Both the transmission and T-case were drained.

I just recently got the rig back out to start working on it some more and went through checking fluids and topping everything off. Filled up the t-case and then went out of town for the weekend. Got home and found a big puddle under the truck. It appears to be leaking where the case halves join together.

Is this pretty common? Has anyone dealt with this before? I imagine I’ll have to pull the case back out and tear it completely down to reseal it. Just wanted some insight before I dive in

 

[Edelbrock]

I would just clean it with rubbing alcohol, and then run a good thick bead of Permatex "The Right Stuff" gasket sealer down the seam. Maybe flatten the bead out with your finger so that its 1" wide and maybe 1/4" thick. I might not look pretty to the catalytic converter thieves crawling around under your truck, but It would certainly not leak any more. Plus the whole job would cost $15 and take 15 minutes to do. Let it site for 24 hours before filling with fluid just to be sure its fully dried.

 

[blue_ls10]

I would just clean it with rubbing alcohol, and then run a good thick bead of Permatex "The Right Stuff" gasket sealer down the seam. Maybe flatten the bead out with your finger so that its 1" wide and maybe 1/4" thick. I might not look pretty to the catalytic converter thieves crawling around under your truck, but It would certainly not leak any more. Plus the whole job would cost $15 and take 15 minutes to do. Let it site for 24 hours before filling with fluid just to be sure its fully dried.

Can’t say I haven’t considered this as an option. I’ll probably give it a shot first and hope it holds. I just need it to hold while I work on the rest of the truck around it. Those converter thieves will be disappointed when they crawl under this rig, it’s already cat-less lol.

 

[Edelbrock]

If you use that specific product, clean the surface well enough, and let it thoroughly dry - it will hold. I have patched slashed tire sidewalls, punctured A/C condensers, fuel tanks, oil pans, and even transfer cases that had the exact same issue as yours. Just got to make sure the area is super clean and dry before applying the product. Spitting on the area and then brushing it off with your sleeve wont cut it. Any oil on the metal will ruin the repair. Multiple applications of brake cleaner or rubbing alcohol, alternating back and fourth with rubbing the area vigorously with a very absorbent cloth like a bath towel or something similar is best. Once you have it 100% clean, clean it all over again, then generously apply that gasket maker. If you do this properly, it will be impossible to separate the cases later without using a razor to defeat the sealant - which is what you want.