My wife's '92 SL1 w/automatic had slowly been leaking transmission fluid since last winter... probably about a quart over the past year. The rate seemed to pick up now that cold weather had set in, so I decided to do something about it.
A quick orientation: Unlike the classic 70's automatic transmissions that I had experience with, the Saturn's automatic has a pan on top instead of on the bottom. And a little bit of investigation revelaed that the fluid was leaking out around the edges of the pan... pretty much everything underneath the seam had a thick layer of grime and ATF on it.
Removing the pan is not so bad. First I had to remove the battery and the battery tray... there are two bolts that are removed from the outside of the wheel well and two that are on the inside on the top. The air intake is also attached to the battery tray - rather than unbolt this, I just unhooked the whole air intake from the air filter and removed the intake and battery tray as one piece. It was still held on by a wire to a sensor - the air mass sensor?
Then there are over a dozen bolts around the perimeter of the pan-top. Many were finger-loose, a sure sign that the seal probably wasn't working too well anymore. I cleaned away a dozen years of grime from pan and surroundings.
There's also an electrical harness that plugs in through the top of the pan. A snap on cover is removed to reveal a single bolt holding that on. Easy to take off.
Removing the pan revealed a "cooked" gasket. The edge on the engine side was hard and flaking away. The other side came off in one piece.
The inner guts of the transmission looked brand new. I'm sure there's some wear because when I've changed the ATF there's always a little bit of shavings in it.
I probably could've bought an "official" Saturn gasket to replace the cooked one, but it was Sunday afternoon and the parts desk wasn't open, so instead I just used some RTV silicone gasket compound to make my own, after carefully scraping off all the cooked pieces and degreasing.
Seems to be holding up well so far today... the leak, if not completely gone, is way smaller than it had been. There's also an O-ring that goes around the dipstick tube, I should replace that just to make sure that nothing on the top will leak for a while longer, but I haven't gone to get the O-ring yet.
How long do RTV silicon gaskets hold up for? Am I probably going to have to repeat this before the next twelve years are done?
Tim.