The fluid looked good the last time it came out? The TCM is supposed to modulate the lockup on the 722.6 rather than doing hard locks and unlocks. Unfortunately that is controlled by one of the solenoids which could have a tiny bit of debris in the orifice. Do you have any way to check for MB-specific transmission codes with SDS or Carsoft? Did you use the 722.6 rated fluid or the 722.9 rated fluid? I'd be tempted to try another change, changing to the 722.9 fluid (it's cheaper anyway) just to see if that clears it up.

 

thanks for response.

the fluid has been changed regularly at 30k intervals. the fluid comes out pretty dark, but i read that this is because of the graphite on the clutch packs - absolutely no visible flakes in the fluid. the latest change has the fluid which supersedes the old part number, so yes, it is also for the 722.9. if you notice in my second video, i can influence the car to not unlock the converter during off throttle - by simply driving aggressively. thus, i suspect that this is all an issue of programming, but i may be mistaken.

i'm thinking that my next course of action might be to go to a dealership to see if SDS shows any trans codes as well as potentially reflashing my TCU to the latest software update - and perhaps performing a gear and torque converter adaptation through STAR. as you might imagine, i am trying to exhaust all other options before visiting the dealer due to their astronomical costs.

edit: wow, i cant believe i forgot this... i suppose i should mention that this is a 2002 c32 (if not obvious from video) with 70k miles.

 

I figured out it was a C32 from your other thread.

Yeah, I'm liking your next step, after looking at the thread. If that doesn't find something or fix it, the next stop is probably a valve body/solenoid pack related fix. Nothing related to that is cheap.

 

dont you think if it was the valve body or solenoid that it would do it every time?

 

Maybe, but it depends on how it's being modulated by the TCU. We know these transmissions have at least two shift programs they switch between. You could be triggering one or the other.

Anyway, if there's someone with a TCU tune, they might be able to solve this in software.

 

well it looks like i'm not the only one with this hiccup.

people have replaced the entire driveline only to have the same issue.

it's definitely an issue between the TCU software and the lockup characteristics of the torque converter.

i dont even know if im going to waste time and money on getting an adaptation done at the dealer. i think im going to go straight for a performance ecu/tcu tune. im sure a good tuner can clean this right up

 

I think it has to do with the TCC PWM Solenoid Valve. Check out the postings in my signature.