I have a BW1356 transfer case (that's still in the truck). Some previous gorilla overtightened the pipe plug in the drain hole, causing a longitudinal hairline crack in the boss. It doesn't extend radially into the case itself, but when the plug is tightened down with Teflon tape, it spreads the crack just enough to cause a slow annoying drip. I tried cleaning the area and using Hylomar sealant before reinstalling the plug, but it still seeps.

Someday I will take it off, remove that cover, and fix it properly. In the meantime, is there any quick-fix, or at least something that can be done without removing the t-case? It is a real PITA to R&R it. The case is magnesium alloy so welding is not an option (certainly not while it's on the truck!)... drilling the crack is not likely to work because the pipe thread will just spread apart again.

I think I already know the answer here but still hoping. Maybe JB Weld?

clean it well and use plastidip on the cracked area... fixed an annoying 8 3/4 gear oil leak at a weld that way.. its till holding fine

then, clean the outside area REAL good and use clear ADHESIVE rtv. it has to be the "adhesive" stuff.
that should stop any errant drips.

If the case is aluminum, you should never use teflon tape. That's most likely why it cracked in the first place. Take the tape off, tighten the plug, smear black RTV around it and cover the crack. Let it sit overnight and should have no more leaks.

Drain fluid completely, stuff rag inside drain hole to collect any stragglers. Clean area with berkibile 2+2. Grab JB WELD. Take a small piece of aluminum foil and smear jb on 1 side. Smear jb on case, dont be stingy. Apply the foil and walk away for a day or two. After the day or two passes, mix more jb weld and smear over top of foil, dont be stingy. Walk away for a day or two. Refill and go about life and drive. Used this method on my srt4s oil pan with tremendous success. Good luck!

What size pipe thread. Some share the same thread dia. and pitch as common straight thread bolts. If so you might be able to run a straight tap thereby eliminating the taper that is spreading the case. I would then use blue loctite or similar thread sealant and call it good.

Drill small hole at the end of crack so it won’t spread farther. Clean well and epoxy the crack and hole (I would install the plug to spread crack to fill)

It's not aluminum, it's magnesium alloy, as stated. And Teflon tape does not cause cracks, overtightening tapered threads in soft material does... And I didn't crack it! It was cracked when I got it (without tape) but severely overtorqued. I really had to lean on it to get it unscrewed.


I thought about drilling and straight-tapping it, then using a matching plug with an o-ring head. It's been a while since I got under there but I believe it's 1/2" NPT which is 14 TPI. Unfortunately 1/2 UNC is 13 TPI...

1/2 npt would be more like a 3/4 fastener not 1/2 inch. But still 3/4 comes in a -10 or-16 pitch. What you would need for free running threads is straight pipe taps and fittings (nps)

It's not aluminum, it's magnesium alloy, as stated. And Teflon tape does not cause cracks, overtightening tapered threads in soft material does... And I didn't crack it! It was cracked when I got it (without tape) but severely overtorqued. I really had to lean on it to get it unscrewed.


.Yea, I did not see that part about being magnesium; however, using teflon tape on soft alloy will allow you to overtighten without realizing you have done so, usually ending in a crack. Sorry for the confusion,

They do make non tapered pipe fittings and taps, they are referred to as NPS vs. NPT NPS fittings use an Oring for sealing but in a non pressure application I would try Teflon tape/ paste or Loctite blue

Hercules brush-on Blue Block thread sealer.