demoer

I'm new to the forum as a member, but have been reading posts since I started working on my sister's W163 (2003 ML350) two weeks ago. She recently moved in from another state, and the truck was a bit behind on maintenance, so I'm getting it back up to where it needs to be. This is the first Mercedes I've worked on -- all my previous experience is with Toyotas and Hondas.

My question is, how often do you guys find the transmission filter on the 722.6 to be dislocated/fallen off when you drop the pan?

The reason I ask is because I encountered this yesterday morning on the W163. I had noticed that the transmission was leaking last week, though since I just started working on this car, I have no clue about how long that had been occurring. It turned out to be what I learned is the "famous" 13-pin connector. I bought a new gasket, fluid, filter, and connector and changed that all out yesterday morning. When I removed the transmission pan, the filter was out of place and stuck to the pan by means of the magnet. The o-ring was still on the neck of the filter.

I had seen a youtube video (Diesel Mercedes channel) before I started the job which specifically warned to be sure that you snap the filter in, with the little plastic tab of the filter fitting into the tiny corresponding slot the valve body. Apparently, the previous mechanic didn't do this, because the tabs were not broken on the old filter, but it wasn't in place. When I snapped the new filter it, it snapped in very securely, so I'm not sure how a properly installed filter would just "fall out."

The transmission worked well before and works well now, though I don't have much experiencing driving it. My sister did say it "feels better" (I've never driven Mercedes before this car, and I was really pleased with the responsiveness and smooth shifting...but my usual ride is a Toyota 3SFE 4-banger engine!).

Thanks for all the great posts on this forum. It has been a tremendous help for me as I get this fun ML back into shape! All I have done so far is replace some vacuum hoses to get it pass emissions, replace the transmission mount (not enough to stop of the shaking in D while stopped -- going to have to replace the engine mounts this week), and some interior trim work (rivets broke on a window regulator, one lock actuator misbehaving). There's a coolant leak at the thermostat, but I'm hoping that will be taken care of with just a gasket replacement.

Maj. Dundee

The ability for the trans. filter to remain in place is dependent on the quality if the filter and O-ring. After market ones could be a shave thinner than what it should be.

As for the Thermostat, you can just change the O-ring, but why not change both for $30 and never worry about it again for the life of the truck.

demoer

Thanks for the diagram, Maj Dundee! I reason why I replaced only the gasket and not the thermostat as well is because my sister said that the thermostat just replaced last year. I decided to save the money and just buy the gasket.

I removed the thermostat today, and it is indeed a new, aftermarket part and works fine, but it was very apparent from the look and feel of the gasket that the previous mechanic re-used the old gasket.

For anyone interested in buying just the thermostat gasket alone, the Mercedes part is #1122030076 and it is cheap ($1 - $3, depending). There is also a Felpro number (#35908) that matches for the ML320, which would be easier to get at a local parts store or NAPA.