Never had a problem like this before in my 20 years of building. Got my converter back from Precision on Oct 31 and installed that night for car show on Nov 1. Put about 30 miles on it and ran fine. Nov 1, I get home and the car is leaving drops on the garage floor. Pulled the torque converter cover and fluid everywhere. Found that seal was totally wet. Converter dry. Pull trans and replace seal. Inspect hub-no cracks, bolt converter to flexplate and turn engine over with my dial indicator on hub and maybe .0005" runout on hub at worst. Put 45 miles on car and everything dry. Drove car this morning and as I got within 100 yards of work saw smoke from fluid getting on exhaust. Look underneath and fluid pouring out of converter cover. Cleaned off so I could get car home and never leaked a drop on the way home at lunch. Put car on my lift at home and cleaned again and fired her up to run during my whole lunch break. NO leaks. All pump bolts tight, O rings on bolts new. Trans rebuilt the week before converter came back. Will not leak until I actually drive for a while and then fluid all over. Either hub wicking fluid out seal lip or ??? Can't be under the car while driving and can't get it to cooperate with me. :biggrin: Any ideas?
Front Seal Leak...
- Thread starter GNeric
- Start date
Well, Gosh Darn-it-to-Mother Heck. I went ahead and pulled the trans back out tonight. I hate to say it but I am getting good at pulling this trans out. 12 minutes tonight even after running it for 45 minutes to get it hot and try and find the leak. Found what feels like a crack inside the converter hub near where the anti-balloon plate is welded to the hub but nothing showing on the outside of the hub. I can actually catch my fingernail on it on the inside. Rubbed a paper towel on the outside of the hub where the crack would be and nothing catches on it. Smooth as can be on the outside so I guess it gets shipped off to Precision, again, so they can inspect and I also get to wait another couple weeks for it's return. 
challengermike
Member
- Joined
- Nov 14, 2005
If you still have the converter cap,you could put in on and tighten it with a hose clamp.punch a hole in it and then pressurize it with a blow gun.Put some atf around the neck and see if you see any bubbles.Dont go nuts with the air pressure or the cap will blow off and scare the mess out off you.At least this way you will know where its leaking from and you could circle it so they see it.Sometimes this doesnt work though,you my need to heat the converter and lightly tap it to see the bubbles.Good luck.I know the feeling how much it sucks to keep pulling the trans and install it.I think i had mine in and out 5 times.
I have a lot of hub caps from all sorts of converters and they are all modified for this. We used to flush converters where I used to work and I kept them when I left and went to Toyota. I tried this and have gone as high as 65 psi and no signs of any leakage. And just my luck that my bottles for my torches are empty. I think my dad has a heat lamp that will turn that converter to 400 degrees in a couple minutes without damage. Thanks. I will try heating it and see what happens that way. I tried the pressure check last night after getting it out at almost running temp. What sux is that it leaked after over 40 miles and then no leak at all.
Maybe Monday I will take it to the machine shop and see if they can magnaflux it... HMMMM
and I kept them when I left and went to Toyota. I tried this and have gone as high as 65 psi and no signs of any leakage. And just my luck that my bottles for my torches are empty. I think my dad has a heat lamp that will turn that converter to 400 degrees in a couple minutes without damage. Thanks. I will try heating it and see what happens that way. I tried the pressure check last night after getting it out at almost running temp. What sux is that it leaked after over 40 miles and then no leak at all.Maybe Monday I will take it to the machine shop and see if they can magnaflux it... HMMMM
MeanBuicks
Scaring the neighbors!
- Joined
- May 24, 2001
Make sure that the converter hub bushing in the pump hasn't pulled forward. When that happens, & it was fairly common with 2004R & 700R4s, it blocks the converter drainback hole in the pump housing.
When I built the trans,I machined 3 spots into the pump to "stake" the bushing into place and used locktite to help hold it. When I had it out the first time to replace the seal, I inspected the bushing and it is in the same spot that I put it. I looked again last night and still put. It is frustrating that when it leaks, it gets everywhere except the converter and hard to tell where it came from. I figure if it came out of the hub, it would be flung off the converter and that would be wet. It acts like the pump housing housing is split and just pukes when pressure is built up. I even replaced the coated washers on the pump bolts in case they were spitting fluid out. Leaked after that too. Never leaked a bit until I had to send in the converter when it burned up from solenoid failure.
challengermike
Member
- Joined
- Nov 14, 2005
I know its a long shot but also make sure the vent isnt pluged.
Made sure that was clear when airdrying after washing for overhaul. I have even taken the magnifying glass out tonight and inspecting every microinch of the pump housing and converter hub as carefully as possible. Thanks for all the responses and I am going back over everything once again just to make sure I am not overlooking anything.
MeanBuicks
Scaring the neighbors!
- Joined
- May 24, 2001
Did you enlarge the drainback holes in the pump. Perhaps a pinhole leak developed?
Pump halves are aligned with the band from OTC. The drainback is enlarged. It was originally a Lonnie Dyers trans from around 4 years ago from the last owner. I went thru everything a couple weeks ago when I had to build it. Drainback is 5/16" and matched at the halves. I have to go out of town to pick up 2 transmissions tomorrow but when I get back I will dig into this some more. Thanks for the help guys. I really appreciate it.
It still could be a problem with the pump. If I had the trans on the floor i'd yank the pump and double check everything inside of it.
Also would check the actual diameter of the converter snout and double check that you didn't lose a dowel pin and that the flywheel has no cracks.
Just my $.02
bob
Also would check the actual diameter of the converter snout and double check that you didn't lose a dowel pin and that the flywheel has no cracks.
Just my $.02
bob
Well... took my Vigilante to where I get my parts from and they have a pressureizing apparatus and they were able to test the converter for any leaks and the converter is solid. I went ahead the pulled the pump out and completely built another to install by next Monday since I have other projects going on too. Found zero cracks and nothing visible with a magnifying glass but I am tempted to take to machine shop for magnafluxing just to see if there is a crack somewhere.
Lee Thompson
New Member
- Joined
- May 24, 2001
Happened to me once
When I drilled the drain back hole larger (front half) It broke through to the out side. Would only leak @ higher pressure. I over looked it many time as I thought it was a casting line.
When I drilled the drain back hole larger (front half) It broke through to the out side. Would only leak @ higher pressure. I over looked it many time as I thought it was a casting line.
This one pump half seems to have a "casting line" going from the left side of the seal cavity (looking at it) towards the top of the body. Out where the outer part of the slide would be. I am going to take and have magnafluxed anyway just to satisfy my curiosity. This got me going and even a few people have asked me if I was going to sell the car now. Going to take a LOT more than this to make me want to sell her.
Going to take a LOT more than this to make me want to sell her.mikestertwo
Well-Known Member
- Joined
- Sep 13, 2006
How much converter to flywheel clearance do you have?
