My '94 E150 has developed a problem with leaking transmission fluid at the pan gasket. It doesn't leak while it's running, only after it sits a while without running. The longer it sits, the more it leaks. It sat unused for about two weeks recently and leaked one and one half quarts during that period.

I know what is wrong at the pan joint allowing the fluid to come out. My question is there a check valve or some other device that should prevent the torque converter from draining back into the pan and over filling it or is that normal and the leaking pan gasket is my only problem?

Gene

 

I had a similar problem with my 82 E100 weeping transmission oil from around the pan while sitting. Fixed most of it by just tightening down the bolts. The Transmission was checked out and a new gasket put in before I got it (know the mechanic). When he drove it out from Phoenix in December, it did not leak. Only in the past month, did this start after driving around our rural highway since then as it's not the best with all the Semi traffic we get. It has not been repaved in over 10 years.

Sometimes abit of more TLC is still needed with an older vehicle. Especially one worked as hard as mine in it's past life as a delivery van. Still has alot of years and miles left in it though.

Found over the years, you just have to get under and check for any lose bolts that loosen up from vibration with any older car. Had to do this with my 79 Cordoba occasionally. Nothing wrong with it otherwise. Just vibration from driving up and down our rural paved highways.

 

I wish that were all there was to it VikingBabe. I had a factory deep pan on it that a friend of mine gave me and I had tried three different times, new gasket each time, to get it to stop leaking without ever completely solving the problem.
That leak was minor up untill recently when I bought another truck and have been driving it while the van just sat idle.

The original transmission in my van had a no torque pan bolt system where the pan had large bolt holes in it to allow a boss below the head of the bolt to go through the hole, through an enlarged hole in the gasket and come in direct contact with the machined sealing surface on the bottom of the transmission. You just tightened them down snugly and that was it. I had the trans replaced with a factory rebuilt unit a while back and it did not have that type of pan or bolts. The deeper pan that I was using didn't either, however all of the replacement gaskets that I have seen have the larger holes which can make them prone to leak if not centered and tightened properly.

So I decided I would fix it for good and get some more fluid capacity at the same time and installed a deeper cast aluminum pan. The pan came with longer bolts to make up for the extra rim thickness, but as I found out later, they weren't quit long enough. The torque spec for the pan bolts is 12 to 14 ft lbs, so I went with 12. While torquing the very last bolt, the threads pulled out of the hole. I could see that the bolts supplied were only engaging about three threads at that point. I measured the hole depths with a depth gauge and found that the next longer size would fit. I requested some longer bolts from the pan manufacture and they are on the way. I think I can get it buttoned up right with the longer bolts.

After saying all of that my main question is whether or not it is normal for the torque converter to drain back into the pan while sitting, to the point that the pan is over full? I'm thinking not because the cold mark on the stick is lower than the hot mark which makes me think that the TC should retain it's contents. What is causing it to do what it is doing?

Gene

 

It is normal for the torque converter to drain back into the pan after sitting for a couple of days or more. Most every transmission will do this. The most common cause of a leak from the TC draining back into the pan is a poor seal on the dipstick boot. This is the little rubber sleeve/boot that fits in the case and seals to the dipstick tube. It mounts right above the pan rail in the case near the right front corner of the pan.

To check it, after it sits for a few days and starts leaking, slide up under the van, locate the dipstick tube and run your finger along the ledge of the case just above the pan rail. If its wet with trans fluid, that's your leak.

Of course, if you have stripped pan bolts or a bad pan gasket, that will do it too.

Steve
'95 Clubwagon XLT

 

Thanks Steve,

I wasn't sure about the drain back issue and the leaky pan was letting me see what normally would be unseen so I thought I'd better ask before it ended up in your transmission hospital.

Hopefully I can get the pan buttoned up correctly and keep the fluid on the inside when the longer bolts get here next week. Mine isn't leaking at the dipstick tube...yet.

Thanks again,

Gene