is it losing engine coolant ? if it is it could be head gasket related.

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Whether you think you can or cannot, Either way you're right!. by Henry Ford.

Thanks for your input. It is not loosing coolent but it is using transmission fluid and oil. There are never oil or transmission fluid spots under the car though.
???

OK, how much oil and trans fluid are you losing ?
meaning are you using a quart every week etc for oil and trans ?
for beginners, to isolate the head gasket problem, go to any auto store or walmart. pick up a bottle each.
I've tested all the products and this company did the trick to stop the leaks.
http://www.barsproducts.com/T20L.htm

http://www.barsproducts.com/E10L.htm

use it for a week and then post your updates. Good luck and I hope this will do it. worse case is going to be what your'e already looking to do . which is repairing. but this might prevent costly repairs. worth a shot.

__________________
Whether you think you can or cannot, Either way you're right!. by Henry Ford.

Thanks for the help. I think it is a bad diaphram [transmission modulator]. I will look in to the stop leak as well. After the shop added two liters of ATF the car smoked like crazy for a day and then it just plain stopped. I check the ATF and it is a half liter or so low again. The trans doesnt seem to slip until it is a couple liters low. Is it possible the trans was over filled and thi caused thye smoke or is it most likely the modulator? Also can toy tell me where the modulator is located or even a diagram and what the steps are to replace? As I said I am in the Philippines and I dont have the confidence to do it myself but I do have a great mechanic as a neighbor but he works on local toyotas and nissans mainly. He is a little intimidated by the Benz. I think will instructions though he could easily change the transmission modulator. Thanks again.
David

I too had monsterous amounts of smoke coming out of my 92 300D. It made no sense. There was no oil in the coolant overflow. No foamy mess on the oil dip stick. I wasn't using oil or water. I did need to add about a quart of transmision fluid every two weeks. The smoke seemed to come only at highway speeds when trying to merge onto the interstate. Then the smoke coming out was so dense, I almost couldn't see the car behind me. When I let off the gas, the smoke cleared up. (ok, I never could tell if it was white, blue, or black. It could have been purple....I was only concerned with the quantity!)

So thinking I've blown a head gasket and not really wanting to attempt it myself, I took it to my mechanic I use for the hard stuff. He quickly told me I had a blown modulator gasket and the engine was sucking out the tranny fluid. It doesn't burn very well so the cause of the smoke was unmasked. So instead of a blown head gasket or a trashed turbo or a crack in the block it was a simple modulator. What should have given me the clue it was none of those was that the smoke was intermittent. Constant smoke would have suggested the other was the problem.
As a side note, my tranny was giving me really hard shifts between 1st and 2nd gear. No more!
Jrags0951@hotmail.com