I'd make a lousy mechanic

Hello Everyone,

Well, I pulled the tranny pan and was surprised to see a gasket on it. So the previous owner must have done a transmission service (I bought it with 85K Miles on it and I believe the factory only puts on RTV). I took a lot of care to scrape off the old gasket and then put on the new filter.

After putting back on the pan, I torqued the bolts to15 lbs. However, one side of the pan leaked. So I gradually torqued it up to 35 lbs. At which point one of the bolts is starting to strip.

At 15 lbs the leak was a fast drip. At 35 lbs it dripped once every five minutes.

So, I've got to take off the pan again and try to figure out what I did wrong.

Can you guys give me any pointers as to what to look for? I was thinking that I should try a rubber gasket instead??

Anyways, thanks for your help.

Best Regards,
Stan

The previous mechanic bent the flange on the pan.
You will have to check it with a straight edge when you remove it.
Tighten the interior bolts first, work your way out to corners.

(I bought it with 85K Miles on it and I believe the factory only puts on RTV).


I have had my trans serviced by the dealer 3 times and all they use is rtv.
Maybe the last service tech didn't use rtv correctly and put on a gasket.

A bent flange will cause the issue so make sure it is flat like Bernard Feltzer said in his post. Purchase a good RTV sealer and apply in accordance with the directions. Make sure you get one that is designed to form gaskets usually a good black rtv will work. When you put it on prepare the surface by cleaning it with denatured alcohol or clean it with throttle body cleaner. Allow to dry thoroughly before applying the RTV. Coat liberally with RTV and make sure to put a bead around all the bolt holes. Reinstall on the tranny and the leak should go away.

If you are going to go the RTV route, let it cure for 24 hours before pouring tranny fluid in.

Keep it neat, you don't need goop and globs all over the place.

Thanks for the pointers FTP Dad, Bernard and others. I put a straight edge on the flange and it is warped/bent. So I put a 1/8 inch bead of black RTV (provided by the dealer) and put on the pan and let it cure for 24 hours.

After putting in the transmission fluid, there was no leakage. However, with time it first started to leak from one spot and now after a test drive it's leaking about two drops a minute from two spots. Depressing to say the least.

I didn't see Bernard's and GTP Dad's mail so I'm going to try it for a third time tomorrow. This time I'll put on a 1/4 inch bead and tighten from the middle first.

Also, I'm thinking about letting it cure a 10 lbs torque and then after 24 hours put it up to 20 lbs. Would that help anything??

Anyways, thanks again for the help.

Best Regards,
Stan

I did a lot of thinking about my leaking transmission last night, and it occurred to me that the bent flange is just pushed down where the bolt holes are and then not pushed down between the bolt holes. In other words, I think that when the previous owner bolted on the pan, the additional force at the bolt holes forced the gasket to compress more and so the flange bent as well.

So it seems that this problem was caused in the first place by the previous owner using a gasket--instead of just RTV.

So as a pointer for everyone: If the manual says to only use RTV, don't use a gasket.


Best Regards,
Stan

I, too, have wrestled with a leaky tranny pan and attempted many methods to stop the bleeding in my 3-sp, 3.0L, '95 Voy. The original, straight from the factory RTV seal began dripping @ 94K miles. I removed the pan, flattened the flange, replaced the filter, and installed a rubber gasket without RTV. This lasted 4 months without a drop. Then one night, it was like open heart surgery was performed in my driveway.

I attempted RTV with rubber gasket, RTV alone, and rehammering...nothing seemed to work. I read somewhere to apply RTV around the flange, slap-on and align a cheaper cork gasket, let set for a half-hour, install the pan, and add ATF. This method has produced a leak-free tranny pan for 15K miles.

Hello Everyone,
Thanks for all your pointers. I tried to find a new pan at a junk yard and the local ones wanted $40 for them. However, at the dealer I got a new one for only $34--can you believe it??!

Anyways, I put on a some RTV, slapped on the pan and it works great. Lets hope that it stays that way.

Best Regards,
Stan

You have to make sure that you clean all the old rtv out of the bolt holes on the transmission . One small piece left over and the bolts will not tighten properly . They bottom out before securing the pan properly .