722.6 Transmission Fluid Change

[Southern]

Since the local Mercedes dealer won't even consider doing a trans fluid change unless you have 100K miles on your car I decided to do it myself.

Thanks to the advice from the members and moderators, I sucessfully changed the trans fluid, filter & gasket on my 98 E320 with 80K miles.

Since I do not have the diagnostics equipment to verify the temp of the trans fluid (80 deg. C), I took another approach. I purchased the transmission dipstick (special tool) and measured the level with the engine cold. The level came up to the 25 deg. C mark. Then I drove the car for 30 minutes and checked the level again. The level was half way between the 80 deg. C mark.

I pulled the drain plug from the transmission pan and drained the fluid into a container. The fluid was filthy, it was a dark brown with no hint of it ever being red. I removed the transmission pan and cleaned it out very well. There was about 1 mm of "muck" on the bottom of the pan. I then pulled the drain plug from the torque converter and drained the fluid into a container.

I installed a transmission pan magnet in the bottom of the transmission pan, installed a new filter and gasket and buttoned everything back up.

I measured the amount of fluid that I took out (7.3 L) and poured 7.3 L of new trans fluid back in. I checked the fluid level with the engine cold (the level came up to the 25 deg. C mark). Then I drove the car for 30 minutes and checked the level again (the level was half way between the 80 deg. C mark).

As always I checked and double checked for leaks.

I do recommend that the trans fluid be changed every 60K miles (as mentioned before from other posts) due to the amount of "muck" and the condition of the trans fluid (filthy). Even though the trans fluid is synthetic, the "muck" and "filth" will eventually plug the filter (which is small in size) causing transmittion failure.