Podguy

When I got back from vacation I found a puddle of oil under the car – a big puddle coming from the transmission. When I removed the cover to the reservoir a bunch of blackish oil poured out – like a quart. Looking through the reservoir the fluid looks black. It smelled bad too. The oil on the ground is not pink or red like transmission fluid, but yellow in color. There was probably another quart on the ground.

It appears either I have discovered an oil well or the differential oil is getting into the transmission. I loaned out my differential plug removal socket and am waiting for its return before I can check the differential fluid level.

I removed the over flow tube that goes from the center of the transmission to the reservoir and no oil came out. I do not understand how there could be enough pressure – especially while standing in the garage to push differential oil into the transmission, especially since none is coming out of the overflow tube.

Any ideas other then turn the car into a parts car? It is one thing to have the car break when driving, but sitting in the garage...

Thanks much

928ntslow

Dan, there are definite smells to ATF and final drive gear oil. if the gear oil made its way into the AT then you would be able to smell it. The only option I can think of is pull the tranny/final drive and remove the FD from the tranny to see why this had happened.

Randy V

That is a 'normal' condition. Normal in that it happens to many. My car did this last month when I did not drive it for 2 weeks.

When the car sits for an extended time, the fluid in the torque converter drains into the transmission case, ultimately overflowing from the breather hole at the top of the case.

This fluid should look clean and red, however - not black as you describe.

Mrmerlin

Podguy, I am chasing a similar problem find the thread looking for cat back system for 84 Euro in it you will find pictures of what has to happen to get to this leak.
Anyway if your oil smells like gear oil there is a good chance that the final drive has decided to leak, there are 4 seals that keep the oil from leaking out, 3 O rings and 1 radial seal there is also 1 radial seal and 1 gasket to seal the transmission. So if there is an internal leak go to the left side of the transmission and look at where the final drive bolts to the trans,, the piece it is bolted to is called the intermediate plate, This plate holds both the trans and the final drive together.
It has a hole drilled into it thats a bit bigger than a 1/8 in drill bit look carefully its about 6 inchech from the bottom of the plate or about 3 inches below the drive centerline This plate houses 2 radial seals, one faces the trans and the other the diff, The diff also has 2 O rings on the drive shaft and 1 bigger one to seal its front portion of its housing to the intermediate plate. On mine the trans had been rebuilt and both of the radial seals were not driven far enough into the housing and the most likly cause was the race O ring was sheared into 2 pieces due to its brittleness. so i was getting a leak when the car was either driven or sitting. The oil was draining from the weep hole on the side of the trans. The purpose of this hole is to let you know when there is an internal leak so the fluids dont contaminate the other system.
To remove the rear diff I removed the rear crossmember and there are differnt ways to do this I removed the whole unit as the picture shows, dont forget to remove the E brake cable from the handle. Good luck

Landseer

Guys, I have something similar occuring to Podguy's post. New-to-me 84 Auto. No known history.

Drained and removed pan. Odd fluid. Not red. Some kind of orange hue. Nasty/weird smell. Been thinking all night how to describe. Chemical, bitter smell, lighter vs heavy. Not citrus. Odd. Maybe there was an alternative trans fluid used on some of these cars????

But no characteristic sulfur gear oil smell.

Definite leak from radial seal towards the front of the car, the one that separates torque converter and transmission. But dry convertor and in front of convertor.
(Also, torque convertor drain plug is welded over, must have been FUBAR)


Replaced filter, intend to add synthetic Mobil tonight, run on jackstands, and drain again and refill with more Mobil later this week.

Will check-out diffy fluid, which I assume should be standard gear oil per manual (not a locker).

Stan, I will probably need some coaching on doing what you did to get tranny out. Am going to put car on road for a week, despite leak, to check transmission function. When it comes out, I need to know whether I need to crack the case or not.

Sorry, don't intend to hijack, but Podguy, it is really strange that you and I have experienced this weirdness.

More data: Car spent last week with rear 1 foot higher than front, back on jackstands. On rolling into level garage, got immediately a half cup of fluid on ground from seal. Maybe I have "it" too. Diffy to trans. Not sure how Randy's explanation could have happened to me, with TC lower, but it could have! Not sure. Damn. Take it apart and replace all seals, I guess.


More insight would be appreciated!!

Mrmerlin

Chris for your problem you have to replace the Converter front radial seal, do the TQ bearings whilst your there, and the front pump O ring seal its about 14in in diameter.

The crossmember will have to come out to remove the transmission, and make sure you dont side load the rear coupler it has to pull off the driveshaft straight, after you remove the rear pinch bolt.

Otherwise you can try to remove the trans by leaving the front portion of the TQ bellhousing in place then the TQ comes out with the trans but must be unbolted from the rear flex plate first,,
The TQ drain should be lined up so when the engine is at TDC the drain plug is visible in the trans grate, install the same way

Podguy

Chris,

The leak you describe is probably coming from the front pump. When I purchased a new torque converster seal the guy at the Mercedes agency suggested the seal on the pump too. It is a common failure. In fact, if I remember right there are a couple of seals inside the front pump. I found mine was hard and cracked.

You can remove the torque converter in the car. It helps to have a tilter but it is not that big a job - about two hours if I remember right. The secret is making a small cut in the bell housing so the torque tube shaft can silde down and out. I used a Sawsall. Undo the bolts holding the transmisson mounts to the crossmember. It also helps give more room if you unbolt the brackets from the emergency brake cable and drop it out of the way. This give you an extra inch clearance.

Once everything is loose disconnect the torque tube front coupler and bolts. Slide the trans back about and inch or so, drop the front of the tube down below the bell housing. This will give you clearance to remove the back bolts in the torque tube and slide it out of the car.

The bolts to the torque cover are then accessible and it can be slipped down and out. The torque converter then slides forward and out. You are then left with a clear short at the front pump.

After removing a few automatics, I found this to be the easiest way to rebuild a torque tube.

Interesting more people are experiencing fluid over flow as a common problem. For what it is worth there is no fluid coming out of the drain between the trans and diff.

Landseer

Wow. Thanks for that set of tips, didn't think it was possible from the front side.
So, its possible to remove the oilpump as well from the front, so I can get to the seals?

And Stan, that helps me get calibrated for rear removal as well.
Have Wed/Thur/Fri off, plus weekend. Wish me luck. Not sure I can get all seals by then.

Podguy, Am curious about cause / source of your gusher leak. Thats a lot of fluid.

I guess you plan to measure what comes out of the differential. Need to know how this turns-out for your situation. Maybe I can preempt something else from the knowledge.

Mrmerlin

Humm you said the fluid is yellow could it be coolant, If its not gear oil?? Possibly a trans cooler ruptured., letting the trans fill with coolant.. I wouldnt start the car untill you have identified the fluid.
Could one of the trans fluid lines have failed over or near the rear of the car? they usually fail above the heat shields so you cant see the drip easily.
You said the fluid looks dark, so drip some onto a piece of white cardboard then drip some fresh trans fluid next to it, compare the colors,

JHowell37

Randy, does this leak that you have described, work itself out after you drive the car some?

Randy V

Yep, pretty much as soon as you start the car the torque converter will refill and the fluid level in the transmission case drops back down to normal.

Landseer

Thanks, I'm going to watch that fill/refill situation.

Found a very old post by WallyP that indicated some trans fluid is amber.
No dripping lines / will check coolant.

PodGuy, you get into that differential yet?

Podguy

Chris,

It takes me a while. I do a lot of thinking before doing anything - especially these days.

Yes you can get at the front pump once the torque converter is out. There is plenty of room and the environment is easy to keep clean.

Now one word of caution here. I have a tilter so I work standing up. I am too old and ornery to work under cars any more. With the tilter it was a piece of cake to remove and rebuild the torque tube. From underneath - if you have a lift if should still be easy. But working on jack stands is going to be tough. - just my personal opnion.

Also some purists might object t cutting the bellhousing with a Sawsall. The piece that is cut out does not compromise the strenght of the car or have a potential of causing future problems. It is covered by the lower bell housing so it is not even a source of water or dirt getting in there. The interesting thing - when I looked at a couple of my other cars someone had already done the same cut so it is not a new idea.

I thought of a cooler leak. But this is the second radiator so I do not think that is the problem. The coolant I am using is the orange stuff. I know - but I had a bunch left over from another job and it seems to be working fine. The coolant level is fine - unchanged.

The oil gushing out seems to be thicker than the trans oil so that is why I suspect that it is diff oil. It has a yellow oil color when on the floor, but when it came flooding out of the cap appeared to be dark.

I will post as I find more information. It would be great to find this was a benign problem and the discoloration of the trans oil just requires a change.

Glenn Evans

The dirty, smelly transmission fluid might have been contaminated from worn or burnt clutches. Page 38-102 of the workshop manual states, under "Check ATF Level":

"Also check appearance and odor of ATF. Burnt friction linings cause a burnt odor. Contaminated oil could cause falure in valve body.

"In this case transmission must be removed and repaired or replaced. ATF lines and cooler must also be flushed."