automatic trasmission is leaking A TON in my 1982 300TD - PeachParts Mercedes-Benz Forum

nickydubs · #1 03-26-2008, 02:16 PM

hello all,

i'm hoping you can help me diagnose a problem i'm having, here goes.

background:
i have never checked my automatic transmission fluid since i've owned this car, about 2 years. i have never had an automatic transmission problem until now. i am mechanically inclined, but this is baffling me. i am currently on the road, over 1000 miles from home (i'm in new orleans, i live in chicago.) that being said, i travel with all my tools so i can do just about anything necessary to the car. i run my car with a two tank WVO system.

problem:
we left last friday from chicago to drive to dallas, a 1000 mile drive that took 16 hours. over the course of the drive we had a few problems (overheating, clogged WVO filter) all of which i've dealt with before. the transmission did not act up at all.

after the car sat for a day in dallas i started it up and the transmission was slipping, the engine would rev up high before it would engage, etc. there were no sizable spots of leakage under the car. i added 2 quarts of ATF and the symptoms went away, but i noticed it leaking from the grate below the torque converter. the leak was surprisingly steady, forming a 4" diameter puddle in under 5 minutes. the fluid coming out was not bright red, if i had to describe it i would say it looked and smelled like clean motor oil (it is not motor oil, mine is currently jet black.) worried that it was a leak i added a quart of stop leak and checked the drain bolt for the torque converter, which was firmly in place. the fluid level was never drastically over the fill line, but i was wondering if the leak was due to overfilling.

yesterday we drove from dallas to new orleans, approximately 500 miles. half way through the drive we added another quart of stop leak. at this point we've added 4 quarts of bright red fluid, and the drip is still not at all red. the drip is also growing, to the point of absurdity. we stopped at a gas station to clean the windshield and it made a puddle that was over 12" in diameter in under 5 minutes. conservatively calling that a 1/4 cup, we should have drained the entire transmission in 8 hours at idle, so it should have drained much faster at highway speeds. at this point the fluid is literally raining out of the torque converter grate. it took 500 miles and 7.5 hours before we had to add more fluid.

in summary:
*it really doesn't look like ATF. is it? it is not power steering as there is too much of it, it is not motor oil, it is not brake fluid and it is not SLS hydraulic fluid. it is not fuel.

*is it my front seal? how much time will that take me to replace? it seems like too much fluid to be coming from a leaky seal.

*any other ideas? since my transmission is functional when it's full of fluid does that mean it's not totally toast and it's worth saving it, or should i just junk it and buy a new car?

thanks in advance for all your help, i appreciate it.
nick

leathermang · #2 03-26-2008, 02:31 PM

"i have never checked my automatic transmission fluid since i've owned this car, about 2 years. i have never had an automatic transmission problem until now. i am mechanically inclined,"
Those seem incompatible with each other.... but you can think about that later...

It does sound like your front seal on your Trans...or the plug dropped out of the torque converter...

I would try adding a couple of cans of TRans-X and see if that will swell up that seal long enough for you to make it home to drop the trans and put a new seal in..

blindwolf · #3 03-26-2008, 02:36 PM

I would bet on the front pump seal. This is an advanced diy. Get a tranny manual, a digital camera and a clean workspace and go for it. If you can rebuild a carbourator, you can rebuild an A/T.

lietuviai · #4 03-26-2008, 02:47 PM

Without a proper manual I would not recommend tearing into a Mercedes transmission. Avoid the ATSG transmission manual since the diagrams are terrible and the steps described often are poorly worded.
I have no suggestions as to what would be a good manual other than one issued by Mercedes.
Rebuilding a transmission is no where as easy as rebuilding a carb. Even rebuilding an engine would be easier.

leathermang · #5 03-26-2008, 02:51 PM

I agree with DJ.... even with a proper manual you are not likely to be able to find the proper special tools which MB is famous for needing.... engine would be much easier..

leathermang · #6 03-26-2008, 02:54 PM

Nick, you need to put your location in your info ...
I suggest you drop the trans and ship it to Blindwolf to repair.
LOL

nickydubs · #7 03-26-2008, 06:20 PM

i've pulled a transmission out of other cars before, just not this one. how long do you think it will take me to remove it, replace the front seal, and put it back in? are there two different possible blown seals, one called a front seal and one called a front pump seal? i shouldn't need to "tear in" to the transmission to change the seal, should i?

the plug has not dropped out of my torque converter, i checked that. it is leaking way too much for me to get it home this way, and i've tried two brands of stop leaks/conditioners. if the general concensus is that i need the seal then i'm willing to try pulling it apart.

any other thoughts?

nick

lietuviai · #8 03-26-2008, 07:28 PM

I've swapped trannys in my 300D in one day with no special tools. They come out easier than they go back in. I haven't looked to see what's involved in changing the seals but I imagine they aren't that difficult.

kerry · #9 03-26-2008, 07:52 PM

Seems odd the fluid is not red. Does the fluid look red on the dipstick? Can you collect some and inspect if closely?

rs899 · #10 03-26-2008, 08:16 PM

If you are ambitous, you can remove/reseal /replace in a very long tiring weekend. But plan on two weekends. The front pump seal (huge o-ring) and the smaller stator seal are not difficult, if that's all you want to do.

nickydubs · #11 04-06-2008, 10:37 PM

well, the end result was a bad pump, the pressed in bushing in the pump was spinning like whoa in there, and since the TC was spinning so excentrically the fluid was flying by the front seal. with the new pump in it's dry as a bone.

leathermang · #12 04-06-2008, 11:28 PM

Congratulations . Nice to hear how something turns out...and that it was good.

lietuviai · #13 04-07-2008, 12:27 AM

How long did it take to do the whole job?

C Sean Watts · #14 04-07-2008, 08:47 AM

to hear a success story on what approaches 'advanced DIY.'

groovinola · #15 04-12-2008, 02:30 AM

Quote:

Originally Posted by lietuviai

How long did it take to do the whole job?

I am a witness to this job being performed (by someone not having done this job before, following along with the haynes manual-fyi which leaves out a ton of steps) start to finish in less than 30 hours (15 of those working), about 10 under the car in and out, 2-3 working with the transmission out of the car and 2 in search for parts. based on what i recently went through, with all the right tools and a garage space to work in to boot, i wouldn't have believed it if i didn't see it with my own eyes. Ah the joys of youth, fearlessness, and a burning desire to get home. New Orleans can be a dangerous place for some people to get stranded.