automatic shifting trouble

I just underwent a similar set of circumstances. Delayed upshifts - "kick in the back" REALLY hard shifts when it finally did shift - etc. You didn't mention cold starts but in my situation it was most pronounced during warm up - after a cold start.

Forget the fluid change. It is a sealed transmission and the fluid is in for the life of the trans.

In my case they were reluctant to physically dig into the transmission, thinking the problem stemmed from faulty programming in the trans computer. They explained to me that the computer was programmed to delay initial upshifts to help warm up the catalytic converter. They inserted all the latest programming updates but the problem still existed so they reluctantly opened the transmission itself. Inspection did not reveal anything obviously broken or badly worn but they wound up replacing the sun gears and several other items.

It would have been a hideously expensive undertaking except for the fact that Mercedes picked up a large share of it under what was called "Customer Goodwill". My share was under $900.00 US.

I hope your situation turns out to be simpler and less costly.

Pat

I have noticed that that it's not as willing to change up when engine is cold, wich by the way seems ridicilous to me that they programmed it that way, when engine oil is cold the least you want is a lot of revs. When i think about it it might be that the problem is worse when engine is warm. It's an itermittent problem. Perhaps i could be the computer. Is it the same one that mangages the engine? Engine has been stalling and been difficult to start when it's cold. Altough it hasn't happened since we put som condense remover in the fuel tank, that may just be a coincidence. Why is the trans sealed for life? Same oil for 15-20 years and possibly

I had a imminent overheat of the tranny on my 1999 E-220 CDI this summer hauling my camping trailer over a mountain pass in very hot weather. this caused the entire gearbox to quit working for a while, but after it had cooled for a while everything was ok. and I could continue the trip (a little more careful on the throttle) I ended up in northern Germany where I contacted the local MB dealer, and they said that MB INITIALLY said the oil should not be changed, but that they now had gone back on that, and recommend oil change every 100-120k km.

He said that what had happened to me was that the transmission had reached dangerously high temps. and the electronics had bypassed the oil to save it from burning up. It should not affect the operation of the transmission (unless it happens often). My cure was to install a thermostat controlled oil cooler in adition to the original one after I had the oil and filter replaced.

Steinar

The synthetic fluid used in these 'sealed for life' gearboxes is only rated for 100,000 mile use by the manufacturer/blender. Perhaps Mercedes and ZF were a bit cynical when they specified zero oil changes because if the fluid was good to 100,000 and deteriorated below spec steadily from then on, most users would get 150,000 miles out of the transmissions before they failed terminally. Perhaps they thought this was acceptable initially but now they have found that more drivers reach high mileage with their cars than they had allowed for, thus a change in policy to recommending a fluid change *every*

Huw