MERCEDES W211 AUTOMATIC - MERCEDES E320CDI W211 GEARBOX OIL GET DIRTY IN 20K - welshpear

Hi guys, I've got a 2003 53 reg Mercedes e320cdi auto. it has done 177k with full Mercedes main dealer history.

It recently developed a slight judder when mild accelerating. I've read lots of information online about coolant in ATF prolem. Hence, I had the car for a Glycol test at local gearbox specialist last week. The result is good and they found no coolant in the gearbox. They noticed that the fluid level was slight low and fluid was quit dirty and recommended a fluid&filter change. I deceided to go ahead for a ATF fluid change and the car is fine now.

According to the old service bills, this car had a Glycol test (Obviously, it must had similar jaddering problem) and a fluid change at 157k by Mercedes dealer 3 years ago.

My questions are:

1. What is the ATF service interval? (according MB, you only need one fluid change at 37k and the fluid will last for life time)

2. Is it normal to get the fluid dirty after only 20k miles/3 years

3.What could cause ATF to get dirty?

Thanks

MERCEDES W211 AUTOMATIC - MERCEDES E320CDI W211 GEARBOX OIL GET DIRTY IN 20K - Falkirk Bairn

I know nothing of the specific car mentioned above but I believe the "dirty ATF" is due to the fact that ATF cannot be drained fully unless the g/box is taken off the car.

Typically up to 40% of the original fluid is still in many gearboxes when the new ATF is added.

If you were to drain, fill, drain, fill............many times you would improve the % age of new AFT to dirty ATF but never get 100% pink ATF. Bit expensive as well.

A bit like a diesel - change the engine oil and 10 miles later the oil is black.