AHHH! transmission is spilling its guts again!

[Dropt72Shortbed]

when i first bought my truck the th350 would leak every now and then. and then sometimes id park it and it would just dump a good 12oz on the driveway. well it happend today.

what gives? i can park it for 30 times on my driveway and when i come back out the next mornign theres a good 2" diameter puddle. and then every once in a while i come out and theres a giant lake sitting under my truck?

any ideas why it spontaneously leaks this much every once in awhile?

looks like i better save the money i was going to use to bag my truck and look into getting the tranny resealed or rebuilt

[tom hand]

I have had the same problem. My problem may or may not be the problem you are having. My problem was cheap pan gaskets. If I parked the truck perfectly level, no leak. If I parked on the slighted hill, big puddle. The leak was thru the sorry pan gasket. The trick is finding a gasket that is worth a crap. The o-ring on the dipstick or seal on the shifter shaft will give the same problem.

[Dropt72Shortbed]

Originally posted by tom hand
I have had the same problem. My problem may or may not be the problem you are having. My problem was cheap pan gaskets. If I parked the truck perfectly level, no leak. If I parked on the slighted hill, big puddle. The leak was thru the sorry pan gasket. The trick is finding a gasket that is worth a crap. The o-ring on the dipstick or seal on the shifter shaft will give the same problem.

i figured that could be the problem but i always park it on the slanted driveway, same spot.

i can leave it there for 5 days without starting it up, wont leak much and then all of a sudden out of nowhere without me driving it or staring it, itll decide to spill a quart on the ground.

i swear its possesed

[sam's 72]

I have one of my trucks in the tranny shop due to this same reason right now. It's a ford powerstroke, with 120,000 miles on it, this is what my tranny guy told me about it. ( I know it's a Ford guys, but this could be the problem with his also ) The torgue converter is slipping causeing a lot of heat build up in the converter, which is boiling the tranny fluid in the converter, causeing it to puke out the front seal. Man this was killing me, cause it wasn't doing it all the time, just every now and then, hell it would go weeks sometimes, no problem, then for no real reason, I would pull up and there it goes puking again. Well, after about 6 months of this the tranny finally bit the dust. I had no problem at all with it, it would shift real good and every thing. Till this happened. Not saying this is your problem, but I would talk to a tranny guy and find out. Would hate to see it do what mine end up doing
Sam

[Capitol68]

I also had the same problem in a 76 van. I swore it was the pan, took it off at least 3 times. Let everything dry ,made sure pan was straight. It still leaked, bad,much worse than urs.I finally took it to a shop. It turned out that it was a large o-ring ( 3 " ) ? on passenger side. About $5 for the part.
Hope this helps
Mark

[Michael A. K. G]

I don't know much about automatic transmissions; all my vehicles have manuals (and I've rebuilt two of them). For manual transmissions, you use black RTV if you suspect there are even the slightest problems with the sealing surfaces. Since manual transmissions aren't opened very often (if ever in some cases), some people just use it routinely. Gaskets can sometimes be hard to find, so you use black RTV for that, too. If you think you are going to have to reopen, you can use blue non-hardening "flange sealant" on machined surfaces only. Some pans are machined and some are stamped.

I know automatics need to be openend more often, but it still is very rare. Is there any reason why you can't just goop the RTV on?

I presume there has to be a vent somewhere. On the Saginaw 3-speed, it's a steel fitting on the top of the extension housing. A vent is needed any time there is a fluid whose temperature changes. You might want to make sure the vent is not plugged.

[COBALT]

My TH400 has leaked since I got the truck over a year ago. Never really a lot of fluid, and sometimes none at all. You're doing the best you can do for a preliminary diagnostic: find a pattern with the leaks. Mine turned out to be parking the truck pointing downhill. Whenever that happened it would leave a puddle. I was also getting a TON of blow-back, so I realized it might be the front seal or converter.

Now that I've had the truck up on jacks at my dad's place for the past month it's left a HUGE puddle, which confirms my thoughts that the front seal is the culprit (we poured the shop floor to have a 1" drop out the front doors). Since pressure in the transmission hasn't been brought up with the engine running the fluid is free to find any hole it can find to run out of. Smart me wiped the pan, case, governor cover, tail extension, and inspection cover before I left it alone a few weeks ago. Now it's magic. The only place there's fluid evident is on the inspection cover (which covers the converter). Therefore, the leak is at the front seal or out of the converter itself!

Now this doesn't take into account what happens when pressure is built back up. Another leak may exist where its only evident when there's high pressure in the case. Therefore, I'll have to replace the front seal, and check for leaks again.

Sometimes you just have to be systematic and check one thing at a time until you zero in on the reason. What sucks is sometimes you have to park the truck and NOT drive it until you find the problem. Patience is a virtue.

Good luck.