Transmission shifting hard

DA3OOR

MEMBER
2012 MERCEDES BENZ E350
3.2L
6 CYL
TURBO
2WD
AUTOMATIC
160,000 MILES

While driving on the highway (90kmh) if I floor the gas pedal for a few seconds (now around 120kmh) and then lift it off immediately, the next gear comes on so aggressively and I hear a loud bang from the back of the car, it feels almost like someone rear bumped into me. I think it happens only between 5th and 6th gear
If I do the same thing but with slightly pressing the gas pedal nothing would happen and the gear would change nicely.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Since it doesn't do this under normal conditions, it doesn't sound like a transmission issue, but rather a worn flex joint on the driveshaft.

When you are full throttle and then let off, pressure is released and there is a drag on the driveshaft in the opposite direction (engine slowing vehicle). If there is play and you hit the throttle again, you can get a clunk if there is excessive wear.

If you look below, pics 1 and 2 explain how to inspect the parts. Pics 3 and 4 explain how to replace the fitting sleeves on the flex disc. I have a feeling if you inspect them, they are the cause of the issue.

Let me know if this helps or if you have other questions.

Take care,

Joe

See pics below.

Images (Click to make bigger)