well today was interesting..... following last weeks installation of my new aluminum transmission pan and new rubber gasket, I noticed it was leaking from the front corners. SO today I dropped the pan and replaced the gasket (this time using RTV as an added precaution) and... tah dah... now its leaking from the front center, even moreso than it was earlier... WTH! So now I have to decide.... do I drop the pan again, s****e off all the RTV and try a different gasket or do I just give up and add a bottle of Lucas!
Are you sure the gasket is thick enough and the bolts aren"t bottoming out ? I always use cork gaskets on the aluminum pans.
I've used a gasket sealer called "right stuff" for problem gaskets before. that stuff seals like crazy but is expensive and holds so well that you might have trouble getting the pan back off later. you can find it in most parts stores in the RTV section
thanks for the cork advice.... that was my plan for tomorrow. Cork and NO ATV, those rubber gaskets just seem like a **** idea to me. So... another 20 bucks in AT fluid and a cork gasket, and I am pretty sure my problems will be solved.
take the pan off. look at the bolt holes in the pan. more than likely theyre "pulled", or "bowed" out. theyre supposed to be flat with the pan rails. i saw that alot when i was wrenching for a living. all you have to do is tap them with a hammer back flat. check it on a good flat surface too, as it could be tweaked too. use a good gasket like primed34 said. re-install it with a 1/4 drive ratchet by hand. dont friggin crank down on it! thats how the holes got pulled in the first place. just snug is all it needs. thats weird to me but it worked for me more than a few times. good luck.
just re read your post. derf... you said aluminum pan? thick cast aluminum? i was referring to the stamped steel stock pans. oh well. for what its worth....
are you sure its the pan leaking? From my past experience working at a ****** shop.....50% of the time its the front pump o-ring or the front seal. Also...I never use cork or rubber gaskets. Best gasket we found at the shop was the black paper ones. Can't remember the official name for them right now. They won't pinch in two or squeeze out. On the aluminum pan....make sure you tighten evenly and check to make sure the gasket flange is fairly straight....lay a straight edge along each side to check it. It doesn't have to be perfectly flat but make sure it isn't bowed.
Cork pan gasket is what Chris uses on all the transmissions he builds for me,,I don't have any leaks. HRP
****** fluid will break down blue rtv. It tells you on the tube not compatible with trans fluid. I learned that that hard way. Bill
FARPAK is the gasket name. I agree that they are the best......hands down. If you have a WITT (Whatever It Takes Transmissions) nearby they have them. Others do I'm sure but you'll have to shop around.
Sounds like txturbo and I have the same experience. If the front pump seal. or more often the large O'ring around the Front Pump leaks and the pan gets blamed. Pull the dust shield and check in there.
I usually find the leak is from the dipstick tube oring or oring on the kickdown cable..leaks down and drips off the corner of the pan.
NO RTV sealer!!! Take off the pan, clean of the sealer and old gasket, chamfer all of the holes on the gasket side. Use the black fiber gasket, tighten the bolts with a 1/4" ratchet. Now find the leak...its either the front pump o-ring or t/c seal ......or 2x^
Permatex makes a special silicone sealer for automatic transmissions. It's their product number 81180 http://www.permatex.com/products/pr...utomatic-transmission-rtv-gasket-maker-detail
I'm using a rubber gasket now and it's doing okay, but I prefer cork. The advantage of the rubber gasket is it's reuseable. I used to get a very minor leak with the rubber gasket, but filing down the mounting flange and torqueing the bolts in the proper order is my trick.
I have built over 200 TH350 and this is what has worked for me. Go to a transmission parts house, or on line, and buy a black neoprene gasket. Make sure the area around holes in the pan are flat. Put the gasket on dry, no sealer, NO RTV, dry. Torque the bolts to 13 ft lbs. Done. Never had one leak.
Yep, When I went to a friend's transmission shop to get a new speedometer drive gear for my turbo 350 he only had cork trans gaskets hanging on the board behind the counter. I bought one and so far no leaks on the big truck's trans.
I use the FarPak type paper gasket mentioned for aluminum pans. there is a brown paper gasket like the FarPak. Both have a thin adhesive on them. If the aluminum pan is a budget unit with thin pan rails, check for cracks and flatness as mentioned earlier
jesus! I should have lived with the small leak! Now it is leaking like a stuck pig. So I am going to drain yet another 4 qts of brand new ATF, drop the pan, s****e away all the RTV, clean, install a cork gasket and ****on it back up again. I am thinking I should drop the dust shield too, because I am wondering if a seal is toast and its not even really leaking from the pan. Damn, i really wish I knew more about freakin transmissions, but that is what its all about.... getting your learn on right? Stupid leaky *** transmissions! Nothing else is leaking on the coupe, so if I can knock this out, then I can deal with the 3 other projects in the garage, but right now, a leaky trans is my first priority.
Ha I sense anger in the ***le but trust me your trans hasn't gave you as much leaking as mine has.4 pan gaskets later the sob still leaks.I just don't care anymore.rubber, cork, it still leaks but rubber ****s
Sounds to me like you don't even know for sure it is the pan, get it up on a lift or stands and find out for sure where it is coming from, before you try to fix it. I have used all of the type gaskets mentioned, and never had a leak out of any of them, they are made for the purpose, and should not leak if installed right.
I can say that the parts stores say not to use gasket shellac on rubber gaskets.I've tried it without and with.and noticed even rubber gaskets seal better with shellac
so here's the plan..... drop the pan drop the dust shield clean all the RTV off everything find the leak (pan, dipstick, front seal, cooler lines, etc) douche in whole thing in cleaner Replace whatever seal is leaking (damn I hope its not a front seal) make sure the pan is flat ****on it back up and fill with fluid What did I miss?
I had a TH350 that wouldnt stop leaking and I used some sealant in a can that had a nozzle on it like a cheeze wiz can. That ****** never leaked again. I found it in the parts store near the other sealants.
The whole deal started after you went with the aluminum pan? If so, really take a close look at it, check it for flatness, a thick plate of gl*** should be fine. Got a machine shop buddy? Have him lay it on a surface plate to see if it has an appreciable rock to it. I've lapped similar things flat with some big pieces of 80 grit and a surface plate. Bob
Check the cast aluminum pan. The no-name 350TH ones from Jegs or Summit, can only accomodate small fasteners heads in the corners. If you are using a washer it will interfere with the sidewall and crack the corner. I found this out the hard way...so I welded the pan, re***embled, and it still leaked, removed and check for flatness, removed ejector pin flash, used gasket cement...Still leaked Ditched the pan, went to an OEM chrome pan, flange head fasteners, cork gasket, red gasket tack, used a torque wrench....Still leaked...Checked shift seal, change to a Miloden dip stick...still leaked.....Finally I just let the damn think leak until it seeked its own level. I think the combination of the rake, and maybe being a little over filled caused the leakage... Now I have two cars with sticks....and one with a glide...NO LEAKS!
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