Hey there. I have a 72 olds cutlass and I am at a complete standstill with this car and it's making me so unhappy! For a while now the tranny has had a very slow leak. Looked like it was from the pan, after changing the pan gasket 3 times I figured it wasn't that as it was still leaking. One day I came home and all the tranny fluid had leaked from the car. I have no idea where it's coming from. I decided to fill up again and test the gears no leaks. Does not leak while I drive it only when parked. After filling it up again it has all leaked out again. I would like to fix this myself however I don't know where to start. Could it be the front seal. So lost and upset that I can get this done! Please help!

 

By the way the car is all stock. Has original tranny. Automatic.

 

check yout tranny dipstick tube....make sure it is into the pan far enough with proper seal. If not, as the car sits the torque converter drains and your tranny pan will fill and leak out at the base of the tube. I did the same, replaced pan seal and it still leaked. Turned out the dipstick tube was rotten and not sealing properly...new dipstick filler tube no more leak.

 

Check rear seal where drive shaft goes into the tail housing. Also check vacuum modulator valve at pass. rear of pan. Both of those were leaking on my '72 d.d. recently. Pretty easy to replace those & not very expensive. Also could be speedo cable gear gasket on driver side.
Maybe clean all the fluid off everything under there & check it every hour or so after doing so. Eventually the leak will show itself.

 

Check the front pump o-ring seal.

 

I had this on a 350 turbo. I checked all the above and still had a leak. It ended up being the kick down cable. The housing was cracked and when the car sat for a few days the torque converter would drain back into the pan. I would have a drop the size of a quarter after a day, after three days I would have more then a quart.

 

Prior to having my tranny rebuild last summer, my th350 would leak while sitting for the week not much but a small puddle, when parked over the winter it would leak alot. I happened to be my speedo cable. Good feedback from all the guys it could be a number of things.
Hope this helps
Eric

 

The speedo seals can be hard to find. I think I eventually had one special ordered from Napa. My kickdown cable seal was the o-ring type and needs to be the correct size.
When I bought my car I had them replace the front seal because it was leaking. When I rebuilt my engine a year later I replaced the front seal again, just for good measure. It still leaks! Someone on here suggested the TC shaft might be rough and chewing up the seal. Just a thought.
Good luck. Leaks suck.

 

This sounds weird but here's what I did. I had a leak like you described. Couldn't find it. I "fogged" the whole bottom of the transmission with a insect fogger I had trying to kill a yellow jacket nest which was in my attic. Then I could see where the leak was. It ended up being a few leaks- kick down cable and the shifter shaft. I'll bet you could do the same thing with some flour or talc powder. Good luck.

 

Greg,
I'll have to try that, thanks for the tip.

 

my car did the same thing and it drove me nuts. puked whenever it sat for more than a few days. did the pan, dipstick and modulator o rings with no change . finally did the speedo gear housing o rings, new red speedo gear and gear seal( the plastic gear is color coded depending on rear gear ratio I believe you can see the color when you unscrew the speedo cable at least on a th 400) and shifter shaft seal. you can get the tool to do the shift selector shaft seal on ebay for under$20 and it makes it a 2 minute job. after cleaning everything up and lubing the gear and seals before installing, no more puddles. a few drops over this winter but acceptable considering how bad it was and I did not get crazy and pull the trans and do everything. hope the info helps and good luck. dave

 

I'm not following. You mean you kind of powdered it up? Kind of like a babies bottom?

 

+++ on that. That's how mine acted too, it was leaking from the pump seal.

 

Yeah, kinda like that...

 

Just curious, did you ever remove the driveshaft when doing work to the tranny? If so you may have damaged the rear seal when reinserting the shaft, especially if you didn't lube the outside of the yoke. That will cause a leak like you describe. Ask me how I know this...