I have had a minor leak that has gotten worse lately in the automatic transmission of my 1988 300E for a while now. I have been keeping an eye on the fluid level (at least I thought.) Earlier on last night, the tranny was shifting fine. Then when I came out later the tranny would stick in 2nd gear. It would shift down to 1st but would not shift into 3rd. Reverse works with a slight delay as it did before. I ended up towing it home as I was afraid to drive it a long distance. I checked the fluid and the level looked high, so I siphoned some out, and the fluid looked dark. I replaced the fluid and filter about 6000kms ago or about 3-4 months ago. This is driving me crazy. Any ideas. I was prepared to drop the tranny and replace the front seal where the leak was coming from, but now I think my problems are more major and I am not a transmission mechanic

The lack of upshift can be caused by low fluid level or foaming caused by high fluid level. If the problem was caused by foaming it would go away after setting for a while.

I have also seen problems occur when the the filter doesn't seal properly to the valve body (causing air to be sucked in during hard driving. You should verify the oil level again making sure you have enough LOOK AT BOTH SIDES OF THE STICK. One side often is much higher than the other. Go by the low side.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Your suggestion of looking at both sides of the AT dip stick is right on the mark. I find it very difficult to get a good read on the level most times.

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• 2001 E320

I have checked the fluid and it was high, so I siphoned some out. It has sat for over a day and still won't upshift. I hadn't added fluid for about a month and it was above the full mark. How could this be when I have a leak? It was working fine at this level till the other night.

i had a similar problem before in measuring the
proper level of ATF. It has to be in between the
two lines of the dipstick. The fluid should however
be hot to accurately measure the proper level. Cold or
warm fluid temp. will result in higher levels of fluid.
To attain the proper hot temp. drive the car for 20 to
30 miles, maybe more in cold regions, and then check
dipstick with engine idling. Hope this helps.

Do you think it might make a difference changing the fluid? It is no that old but like I said it is quite dirty. Possibly the previous owner didn't maintain it, or do I have more major problems.

I took the pan off tonight and it looked like there was black dust or something in the fluid. The dust, or whatever it is, did not look that thick. Could this be a clutch? Which one would be the one that engage for 3rd? I talked to a friend of mine and he said it could be one of the plungers. I really don't know alot about automatic transmissions, and I am afraid to take it somewhere for fear of getting taken advantage of. I have done lots of mechanical work on all my cars I've owned. Where could I get more information for this transmission? I understand that the dealer does not have manuals anymore, now they have cdroms, which from my understanding, do not have a lot of info on transmissions.

Third gear is clutch pack K1. From the way you describe the fluid, I would say its time for a rebuild.

MB sells those trannies rebuilt for somewhere around $1800. Its hard to get a shop to go this way as the rebuilt trannies have a very slim discount. If you don't have a local specialist and are up for the exchange, buying from MB might be a solution. Its also hard to get a MB dealer to do the job for the price of the tranny and 6 hours of labor. I have heard of dealer prices from $2500 to $4000.

A good independent with MB experience should be able to do the job for less than 2k if your unit is rebuildable. We usually do it for around $1600: rebuilt, installed and adjusted.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

So I pulled the tranny out and took it to one of my friends shop who specializes in Mercedes. When we were looking it over, we noticed that the kickdown solenoid housing was cracked, it had been cracked for some time as it had dirt in the crack. He is going to take it apart to see if there is any other damage, but could this be related to my problem?

Absolutely. Fix it, and for God's sake change your fluid and filter. Have your tech flush the entire tranny, several times. Also flush the torque converter. Get all the crud out. Does the fluid smell burnt?
If the only parts that need replacing are the clutches themselves (soft parts). it's not too expensive. But if the metal parts are scored (hard parts)or have lost temper you might consider a rebuilt. Most techs can rebuild the present tranny for around $1800, but won't warranty past a year. I believe an MB remanufactured unit comes with a 2 year unlimited mileage warranty.
I have had similar discussions with my tech concerning my 300TE 4M 91MY w/ 69k mi. I experienced a problem where the tranny shifted down from 4th to third at highway speed. After checking out and finding OK all the control parts (vacuum modulator, bowden cable, kick down switch, and shift solenoid) he suspected the valve body. Pulled the pan and filter, cut open the filter to look at the screen and paper element and discovered a clogged paper element. Clogged I might add with clutch debris; chunks - not just dust/goop.
He flushed the tranny out twice, popped a fresh filter in, dumped some new fluid in and it shifts like a champ, and HOLDS it!.
The bad news is he doesn't think it'll last much more than 5k more miles. Ergo the rebuild or reman question.
Hope this meandering message helps.
Best,

__________________
Hazen Arnold
Happiness is a well stocked
garage.

I replaced my tranny with a used one. Just my luck, finished putting the tranny in and it has two leaks. One is in the same place as the original, around the front pump seal, I am assuming, and the other one is from the right rear corner, could be pan gasket??? Looks like I have to pull it out again. What a pain.