M-a-x-G

I merged with a right turn into another road at an angle of 80 degrees between the roads.
The gearbox wouldn't shift into a higher gear.
I stopped the car. Shifted into neutral, then back to D and drove home 100km without a problem; no lights coming on, etc. This happened two days ago. All seems good.

What is going on here?

Could the tranny oil appear low given the centrifugal forces around the bend? But I was driving at no more than 30km/h (20miles/h) just starting at the traffic lights.

It is a W221 2011 S350 7G S-Class...
... any suggestions?

alx

During high g maneuvers the gearbox will hold lower gears longer. Also it is possible that the tcu has learned some garbage and is confused. If you had a problem you would not be able to get the car to behave without shutting it off and restarting it. THe fact that you were able to continue without restarting it makes me believe this was either as designed or a fluke.

conrinue driving normally and if this starts happening more often have the tcu reset (if no errors). If errors remedy as required.

M-a-x-G

Thanks alx for the reply -- makes sense... I wasn't too fast, but the road was leaning outwards in that area; and good to know that when the 7G is broken I will know for sure

Finer6527

Hi, When I first got my O7 S550 it got stuck in 2 or 3 gear when going around a corner. This happened within the first two weeks, so I was unsure of the car and its functions. I thought that it might be low on trans oil or needed service since the car had 58k miles at that time. I serviced the trans and all seem fine after that until I did a tight turn one day and it stuck in 2nd again. I looked at the selector button on the dash and I had hit the button on the back side of the steering wheel which kept it in 2nd gear. I have hit that button by accident on tight turns since then but can feel it and corrected the gear selection. Not sure if it was the trans service or me hitting the button without knowing it, but after 5k miles I have had no other issues.
How long ago was your trans service done?

bensitto

Get the transmission checked out at your dealer, hopefully you are still in your warranty/extended warranty period. Speed sensors (TCM) go bad on the 7G-tronic transmissions, if it isn't corrected early, can lead to the entire valve body (TCU) needing replacement, and further damage could cause the entire transmission to go bad. The older Siemens branded TCM or Speed Sensors are no good (Should have been recalled). The Newer Continental branded ones are the updated ones.

Good luck!