Stopping leak at Vacuum modulator C4 Tranny

For the life of me I cannot get a leak from around the vacuum modulator on my C4 tranny to stop. It's a new modulator. I put teflon tape on the threads and used the little paper gasket it came with. I've gotten it tight but I still get a pretty decent drip. I know it's coming from there, as I have a new pan gasket, and I put baby powder all over the tranny, and that's the leak.

Is there some other sealant that I could/should use to seal this up?

Thanks in advance

Mike

Use some Lock-tite "Gasket Maker" on the threads and paper gasket. It only takes a thin film (.010") on both sides of the gasket. They don't usually leak, be sure to check the surface for scratches and cracks.

Thanks.. I'll give that a try. I was curious about the surface as well, and the potential for cracks, if it was tighted too tight at some point. Sure hope it ain't cracked cuz that will sure suck!

Well, I THOUGHT that worked (may still have, and perhaps I have another small leak). I took the VM out.. inspected the area around the mounting point.. All looked fine. Put gasket maker on and reinstalled.. Woila.. seemed to work. Car sat still all through dinner etc with no leak.. normally leaks a small amount by that point. Drove it a bit, pulled into garage and now have a small spot again. Aggrivating!!!! Could be another spot, but I'll be damned if I can find it. Replaced both front and rear seals about two months ago, replaced pan gasket, new cooling lines (no leak there). Will see in the AM.

Fingers crossed


Mike

What about the o'rings on the cooler fittings where they screw into the case? Would run down to mod area

Didn't realize there were o'rings on those fittings... See that's why I love this board.

Thanks Greg.. Will check that out tomorrow

Mike

Don't the case have Pipe thread with Brass compression fittings screwed into them?

If you still think the leak is near the module, try to look above the module with a mirror and drop-light and look for a crack in the case...

I don't remember the configuration of the fittings... I do think the case has pipe thread, and I think the fittings were brass, I just don't know if there were compression fittings or not. Will have to check in the AM

Thanks

Mike

Originally Posted by FEandGoingBroke

Don't the case have Pipe thread with Brass compression fittings screwed into them?

The ports are NPSM if I remember - STRAIGHT pipe thread, not tapered. If you thread a tapered NTP fitting into the case you can crack the case.

I was thinking about the coooling lines having tapered pipe thread to seat the brass, then a regular comp fitting on the cooler lines... Been a while on my last C-4 takedown...

Thanks cKelly.