xsever

Hello everyone,

I changed the transmission fluid and filter in late December 2020 and I followed the MB WIS instructions to the letter after watching many YouTube videos as well. I document this here.

Now I am not sure if this is related to the fluid change or not, but over the weekend, my car started jolting when downshifting from 4 to 3 and started slipping when upshifting from 4 to 5. I scanned for codes and got nothing. After the transmission specialist and I checked and confirmed the fluid level and then did an upshift and downshift adaptation on the highway, the car was not accepting the 4 to 5 adaptation no matter what we did. The adaptation for the rest of the gears was fine and they all shifted silky smooth.

He concluded that we need to change the solenoids and then do an adaptation reset and that was successful. The car is back to normal now with the new solenoids. I am going to drive it for a bit to make sure everything is ok before doing another upshift/downshift adaptation update on the highway.

You have no idea how disappointed I was and still am because a well-maintained car with 53,000 km / 33,000 miles should not suffer from such a problem. This is not the Mercedes Benz quality that I was raised with. This could very well be my last Merc.

Anyway, I thought I'd post this thread to help others should they face this problem.

Cheers.

dill_flo

Hello,

While I love the idea of low mileage as well, judging from your purchase in it’s original state I would not expect the best of “Mercedes Benz Quality” as you so describe. You bought a car that was moderately wrecked, with such low mileage from the original build date, as it probably sat around not being used for most of it’s life before you. Therefore, when a car like this, or any car for that matter sits for long periods of time without functioning or having fluids and it’s mechanicals moving around (IE: transmission) and so forth, things go wrong, usually at an increased rate. While I agree that the solenoid issue is not acceptable, I do not believe this should taint the reputation you hold of Mercedes-Benz. You did not exactly start at the utmost level of “Mercedes-Benz Quality" in the first place.

Regardless, nice car, I hope that it works out for you.

Take care.

(Edit: This is not an attack on your viewpoint of the quality issue, just a different perspective. I have reviewed your entire restoration thread of this specific car. I admire your dedication to the car and enjoyed seeing it be rebuilt and come back to life.)

Adi-Benz

I was going to say theres a possibility that it could have been maybe lightly attributed to the accident, not sure. I haven't heard many people change solenoids on these cars before

xsever

Thank you for taking the time to respond and I do not consider this any attack of any sort. I posted so I inform others and so I receive constructive responses like yours so thank you again.

I totally agree with you regarding the car having sat around for longer than usual but that occured before it was involved in the accident. In all cases, I was ready to deal with that and to replace any parts that will fail due to age not due to mileage but I'm having a hard time believing that a solenoid will go bad because fluid didn't go through it. I even made sure the transmission fluid was changed at the correct time interval set by MB although the mileage interval was too far out.

In other words, I expected exposed rubber and plastic parts like mounts and bushings and pulleys to go bad but not solenoids that are sealed and protected inside the transmission. You get what I mean?

The transmission specialist was sooooo unsurprised with this problem due to how often these 722.9 transmissions are coming in for repairs.

Funnily enough, I called my friend last night who works at the local MB dealership to ask him about the 7G and the 9G and he shared the same opinion as the transmission specialist. He said they're also replacing too many valve bodies on the newer 9G units due to similar problems.

I don't know but MB transmissions have turned into a scary adventure after the bullet proof 722.6 which I had in my CLK w209.

Oh well. Thanks again for your kind words and the ensuing constructive discussion.

xsever

I cannot rule anything out but the accident occured at the 9000 km mark whereas the car now has 54000 km. Did it not like the new fluid maybe? Seems more like it. I don't know.