pathfinder_88

New GL63 owner here approaching 60,000 miles. I've noticed that light throttle shifts in comfort mode are fairly pronounced and somewhat erratic. My expection is that the upshifts should be smooth with minimal rpm change but there seems to be a fair bit of a flaring in the few first gears on upshifts (brief rise/fall of rpm) and I get the occasional rough downshift (I believe 3-2 gear). This becomes quite noticeable in stop/go traffic. In comfort or sport under hard throttle, not really any issues, even with more power from a tune. No issues at highway speeds between 6-7 gear. I've done the engine mounts but the transmission mount is original as far as I know. I'm aware of a bulletin for a re-flash around 2014, not sure if that has been done. I'd consider a TCM tune if it resolves these issues. Experienced owners please chime in!

pathfinder_88

Not wanting to pay the TCU tune prices of US companies, I've ordered a flash device from JF Automotive in the UK following some research and positive reviews on an ML63. I'll be sure to report back on how this goes.

mercboyw212

how did it turn out does it raise torque limits

pathfinder_88

Unfortunately, my issues appear to be more than just the normal tune. I’m waiting to see if my aftermarket warranty is replacing the transmission and torque converter. If replaced, I’ll try the module again. I didn’t really notice much difference but likely due to my transmission issues. Of note, JFA said they would refund at any point if not happy.

NolaGL550

Did you perform a transmission fluid replacement with the pan off? You should try changing the fluid, change out the filter, and flush the trans cooler and drain the torque converter. My 2015 GL63AMG I bought earlier this year at 57,500 miles had a rough shift in comfort mode as well. These things are driven hard by the previous owner and likely reaching the limit of the clutch wear adaption with the fluid at that age and mileage. I performed the trans service with torque converter flush at 60k miles in March, and performed the trans adaption at the same time. Fluid used was 9L of Ravenol at MB spec for the 722.925 7G in our vehicles. I used my Autel scanner to check fluid temp per the MB WIS service guidelines, and drained the fluid at 40°C until the trickle, then tightened drain plug. Don't listen to MB on their transmission service interval recommendations. They are off by about 30k miles. I would recommend doing the fluid service every 40-50k miles as it's just an afternoon in the garage and $120USD worth of fluid and parts. The tools on the other hand are a bit more expensive (Autel Maxisys scanner/programmer and CTA trans fluid transfer container/pump setup).

pathfinder_88

I had the dealer do a trans flush as well as a re-adaptation. I also had my Indy do an individual adaptation for each gear and it has made no difference unfortunately. Vehicle was elderly owned from new.

cmginc

Welcome to the "personality" of an AMG. My GL63 has done that since new. 6 1/2 years later, nothing has changed.

NolaGL550

Then you have done everything that's necessary to ensure the 722.925 is healthy. Since you are certain it was not driven hard, then it's just the "personality" of this transmission and the calibration. I would definitely not have it replaced nor rebuilt...but that's just me. If you are intent on solving this so it shifts to your expectations, then the most I would do is open up the pan again. Replace the trans electrohydraulic control unit and control solenoids, refill, and run the re-adaption. If that doesn't solve it, then it's definitely just the way the trans works in Comfort mode with the lock-up style torque converter. Best of luck!

pathfinder_88

My first suggestion was to clean the solenoid screens and then potential replacement of solenoids and/or valve body. I suspect the warranty company doesn’t want to risk spending more money with no “guarantee” of a fix. I appreciate these transmissions are a bit clunky and I can live with this. This particular one seems to have a mind of its own and is above and beyond what I would consider acceptable. The Indy shop also agreed its behaviour isn’t normal. If they want to put a new one in, have at it.

pathfinder_88

An update for those researching this. Our GL63 has been returned to us after having largely been in the shop for about five months. It was a comedy of errors but it now has a new Mercedes transmission and torque converter thanks to warranty. I suspect there was nothing actually wrong with the transmission however the warranty company wanted to replace it rather than dig into the valve body. The first torque converter put in was deemed faulty and a second one ordered from Germany. After driving it last night I'm still not entirely thrilled with how it is shifting, especially the 2-3 shift under light throttle still seems abrupt/rough in comfort. Full throttle shifts are good. The Mercedes dealer completed the adaptations however we were told that it may take additional driving to smooth out. Time will tell I suppose.