Cracked Transmission Case

Looking for some advice here...

While replacing the manual transmission fluid in my new to me 2002 Jetta TDI, I managed to crack the tranmission case by tightening the bolt for the power steering line bracket too much. Either the bolt for this bracket was too long from the factory or the previous owner lost the original and replaced it with whatever he had laying around. I tighten the bolt, it hits the transmission casing on the other side and now there's a crack. It's very small, stretching from about 2 inches from the back of the transmission case on the drivers side, around the corner about two inches on the back of the transmission case. I don't have a good picture, but hopefully that makes sense.

I did attempt to quickly repair it using JB Weld, and that held for about 100 miles to where I have a small leak again.

What do you suggest my next steps to fix this would be? Here's my thoughts:

1.) Stop drill the crack on both sides, repair again with JB weld and hope for the best. Stop drilling concerns me as I do not know what is on the other side and I'm not too sure I'd like metal flakes hanging around in the transmission.
2.) Stop drill the crack and use HTS-2000 instead. First time using a torch, and not sure how I would fair with the transmission fluid still seeping from the crack.
3.) Buy and replace the casing with a new/used case. Not sure on the degree of difficulty this may pose. In my research, there's a special procedure to crack open the case but I can't really find much info beyond that.
4.) Buy a used transmission and replace the old one. Not sure how challenging this would be, but from the guides online it seems pretty straight forward.

Any help is appreciated

You can certainly try whatever drilling/epoxy effort you like, at this point you really do not have anything to lose.

If it does not work, best bet would be to find a used transmission .. and if you cannot find a TDI specific one (with the same code) any 02J trans can work, you'd just need to swap out the innards from yours. I would want to have someone familiar with that sort of thing to do that. Not hard, but perhaps not something you'd want to attempt on the bench for the very first time.

I have a cracked case in mine too! I found another used diesel trans and that has been in there for a few years.

Mine cracked at the front bolt hole for the dogbone mount. I am going to see if my fabrication shop can weld the crack and re-tap the hole.

It seems that these are soft and care needs to be taken when ever wrenching on them.

Replacing the case requires reshimming the transmission after taking measurements with the case halves installed with loose bearings. This is a lot of work.
Best bet is to install a used tranny.
The easiest bet is that when you drill your stop drills, you could look at tapping them and then using bolts to press something into the crack. So you could either get a compression seal or give your JB weld more surface area to glue.

JB and other epoxy type solutions, need a really clean surface to adhere to. If the transmission is seeping fluid through that crack and you’re trying to put epoxy on at the same time it’s bound to not work for very long.

Drain the transmission, or at least get the fluid level below the crack clean it with some carb or brake cleaner and try again.

I agree with TDijarhead and Oilhammer.

I'll give you this personal experience.

Two cylinder air-cool Kohler engine on a Wood Miser Saw lost the governor and revved full throttle and basically blew ... parts everywhere inside. We (it belonged to a friend) cleaned up the mess and ordered all the needed parts to make it whole again. However, there was that gapping L shaped hole in the side of the Aluminum Block.

Well, we cleaned it super clean, hammered down the edges, and then using a grinder, cut a small groove along the crack. Then, applied the Old Fashion JB Weld... That was in the summer of 2001... that engine is still in service today with zero oil leaks. Keep in mind, that engine block runs far hotter than the TDI transmission.

Lastly, I've replaced several TDI oil pans that had been repaired with JB Weld with no leaks.......

Hope this helps!

Jb weld works wonders. I have also found the super fast urethane window weld glue does wonders if you need something to flex. The surface must be very clean and give it time to dry. Try pulling your front windshield out sometime if you want to know how hard it will stick. The other thing that works wonders on these kind of problems is fiberglass resin and fiberglass mat or cloth. This gives you a larger surface area to glue onto. Sometimes I have put the JB weld on the cracked area to seal up everything and smoothed it over and then covered it with a few layers of cloth. You have nothing to loose for a few dollars and a little time.
Welding is always scary on these type of cracks as you heat up and distort other parts in the process.
I have done similar things but have found if I caused the crack then it generally will not return since it is not a normal structure stress crack or a crack by a gasket with pressure.

Get a mobile welder out to take care of it. Folks have had success with similar repairs. Professional welders are cost effective.

clean thoroughly and squeeze some ultra grey silicone in the crack... i'm using this on my 02M six speed and it had a small hole at the bottom of the case ... no sign of leakage whatsover, ultra grey is high tensile, remains flexible and does not flake off

If you welded or brazed, would the case still be compromised assuming it doesn't completely fill the crack?

I'd go with your #2 and then keep #4 in your back pocket. Even if the repair didn't hold up you could deal with it until you found a good deal on a replacement.

When you drill - instead of draining it first you could carefully punch thru and use the fluid in the trans to flush the drill holes. Messy, but any shavings should get pushed down the holes. After repair I'd drive it around the block and flush it one more time to be safe.

FWIW, I picked up my DD (03) last spring with known transmission issues but still drive-able. I kept driving it until I found the deal I was waiting for and replaced with a BEW trans that only had 120k on it for $100 (long story). Frans (dutchautoparts.com) has pretty good prices and was my backup plan in case my trans completely died before I found a good deal.

after all that.... hard to argue with jimbote's answer. lol