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Leak from Hell



I've got a tranny fluid leak that is driving me crazy. It seems to be leaking from the pan gasket. I replaced filter/gasket but did notice that Chevy states a new pan(deeper) may be required because of their new filter. I figure the pan is rocking slightly on the new filter causing the gasket to not seal properly. anyone dealt with this? It's driving me crazy.:r :r :hb :hb. If I,m going back under it's gonna be the last time.:mad
This is on the 82. Sorry I should have posted it there. Same tranny though;)
Did you take a few moments and flatten out the edge of the pan before reinstalling? If not, here is why you should.

The pan bolts will dimple in the pan flange as you tighten it. This causes it to be very tight on the gasket at the bolt, and loose between bolts.

It is a good idea to take block of wood and a hammer and tap it flat before cleaning it all up and putting it back on.
Hi Chris,
The pan I have does not have the continuous flange. The flange stops at each bolt hole then continues. I am aware that there is a continuous flange on the newer pans. I used the cork gasket as recommended by GM. The pan did seem in good order and all surfaces were clean. I could crank down on the bolts but I don't think that is the problem. I'm still wondering if I need to buy the deeper pan that they reference in the kit from Chevy. I don't know what the torque is on those bolts off hand but I don't believe it's that high. This is one of those annoying problems and may be worth the price of a new pan.:hb :hb :r :r

By the way, I normally don't use gasket sealers on this work. What's your opinion on them for this application?
Don't use gasket sealer on the trans pan ever. The last thing you need is RTV silicone floating around in the trans pan.

I have never seen a trans pan that won't warp a tad after being installed even once. Back in the "dark days" I worked at Jiffy Lube and changed my share of trans filters, and yes, did several repeat jobs until I figured out how important it is to make sure there is no warpage in the pan flange.

Also, I prefer to buy filter kits that include the rubberized gasket as there is less distoration and less chance of a leak.

I am not sure what the problem is needing the deeper pan. I have seen where the orginal o-ring seal is stuck in the trans and the jobber will put the new seal on the new filter and try to jam it all up there. That will make the pan and gasket surface not fit right at all and the fluid won't travel proper through the filter.

Trans leaks are a pain in the butt.
The deeper pan issue is a notice posted by Chevy in their filter kit. It seems the neck of the newer filters are longer and in some cases the pan may have to be changed.( filter bottoms out in older models) As far as the gasket type, it's the one GM provides. I could go and get a rubberized one. I've got a call into Chevy regarding their notice on the pan. I'll keep all posted. Thanks for the input Chris. I will take a hard look at any possible warpage if I stay with the old pan.
Just got off the phone with Chevy. Pan has changed 3 times. Problems on the older cars. Looks like a $33 investment is in order.
I've always used NAPA transmission filter and gasket kits. There are two different kits for the TH350 trans that I know of. One of them always fits correctly without a problem or a leak. NAPA's filter/gasket kit for a TH350 is about $6.
Thanks DDL,
I'm running the 700 tranny but I think when I replace the pan I'll go with the rubberized gasket as Chris suggested. Does NAPA use the rubberized?
I use WIX filter kit no problems here,also wile pan is down get one of these B&M#80250!do use thread tape on this. I also spray my gasket with Permatex High Tack sealant#80065 (99ma) Ido coat it 2 times this stuff works great. Dont forget to spray break cleaner in all bolt holes and on bolts must be clean,I use VIBRA-TITE, formula 3, 248-362-1209,I put this stuff on the bolts. local bolt and screw co should have this. I know this is a little much but NO LEAKS HERE.
Thanks for the input. Believe me, I'll do everything possible to make this the last and final fix.;)
NAPA has either, your choice, cork or rubberized. I use rubberized because it comes off clean next time with little or no scraping. They have kits for every tranny, even my mopar daily drivers. I do all my transmissions every 30k miles, no sealer, no permatex. I haven't had one leak yet. Just remember to get both surfaces very clean, alternate tightening the bolts, side to side, starting in the middle and working your way out. Don't over tighten! This is not near as criticle with the rubberized gasket.

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