Oil pan - Use gasket or Hi Temp Red RTV

[Car Doc]

Lots of trannys are sealed from the factory with RTV. Toyota's Aisin Warner units are one example.

Since I work on Toyota's for a living I see lots of dry leak free trannys.

[K7LN]

Lots of trannys are sealed from the factory with RTV.

The factory offers a nice clean environment with a transmission that has never seen fluid and is probably inverted when the pan is installed. Crawling under a dirty old truck, scraping RTV or gasket material, and the steady drip, drip, drip is a little different.

[Car Doc]

The factory offers a nice clean environment with a transmission that has never seen fluid and is probably inverted when the pan is installed. Crawling under a dirty old truck, scraping RTV or gasket material, and the steady drip, drip, drip is a little different.

Yeah aint that the truth though! I do this stuff every day and wonder how they expect us to make a living at it working upside down and twisted around and sideways!

[Gale Hawkins]

The factory offers a nice clean environment with a transmission that has never seen fluid and is probably inverted when the pan is installed. Crawling under a dirty old truck, scraping RTV or gasket material, and the steady drip, drip, drip is a little different.

Some of use have clean old trucks and we like the way RTV can help us keep them that way.

RTV is especially nice to attach a gasket so it stays in place during the install process. I like it for the valve cover to help insure it stays dry.

I still like to use a gasket when possible but use a thin glaze of RTV for security.

[yankeerider]

Interesting - I do not drive it daily, only a few times a week (about 7k miles/yr).. So this may be the problem - what am i looking for in trying to see if it is the anti-drainback valve?

Brian

If you drive it a few times a week, I doubt that it's the issue I described. The easiest way to check is to pull the dipstick before starting the engine and see if the level is high. (The level will drop after starting because the pump will refill the converter.) You might want to check the level after it's been shut off for an hour, then after sitting overnight, etc to see if it's rising.

Another check from underneath is whether there is evidence of transmission fluid on the outside of the trans case above the pan gasket. In my situation, the pan gasket served as a "trap" for the fluid, so it looked like the leak was there, but the leakage was just pooling there before dripping off.

[timswi]

Sure it does....it's used in place of traditional gaskets in lots of applications. I just replaced the intake manifold gasket on my Ranger, for example. The replacement gasket doesn't even include the rubber gasket inserts that seal up the front and rear manifold-to-block gap. A tube of RTV is included and a bead is run along the top of the block after the block and manifold are cleaned and dried. As the manifold is set in place and torqued down, the excess oozes out. If there were no RTV in there, the open gap between the manifold and block would be about 1/8", and there would be oil leaks aplenty.

RTV is used in many such applications....transmission pans just aren't usually one of them. And for good reason.

What I should have said is that it's not a replacement for a gasket. I have done many intakes where you have to gob them up with RTV, but they are designed that way. I would never use RTV alone on valve covers, water pumps, tranny pans, differentials etc....They were designed to have gaskets, so I put them on.

One of the slickest things going on now is the use of O-rings instead of gaskets. The first one I ran into was on a Lumina water pump years ago..That was actually a pleasure to replace. I've seen that on lot's of other things since then and they generally don't leak.

[orezok]

Gee, it doesn't say anything about cleaning the surface areas. If the manual doesn't say it, I guess we don't have to do it. So much for the manual.

I thought that that would be obvious to even the most amateur mechanic so I didn't post, but here it is for those who need it.

[K7LN]

I thought that that would be obvious to even the most amateur mechanic.....

I had to pull your string a bit. Manuals can be so out of date and seem to be written by non technical people and never reviewed. Mopar seems to be the worst with errors and omissions.

[Car Doc]

One of the slickest things going on now is the use of O-rings instead of gaskets. The first one I ran into was on a Lumina water pump years ago..That was actually a pleasure to replace. I've seen that on lot's of other things since then and they generally don't leak.

Welcome to my world I absolutely agree it is the best way of all! Nearly all the covers and housings on Asian cars have been o-ringed or RTV'd for the last 30+ years (rethinking the time line gets away fast) you rarely see a Jap car leak oil because of that fwtw.

[K7LN]

One of the slickest things going on now is the use of O-rings instead of gaskets. The first one I ran into was on a Lumina water pump years ago..That was actually a pleasure to replace.

Why did you have to replace it? OK, bad pump not bad O-ring. I've seen some of the O-ring installations leak because the O-ring took a set after many years. My experience with this has only been with Mopars.