SL55/63/65/R230 AMG: SL65 Transmission hanging
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Senior Member
Joined: Nov 2012
Posts: 488
Likes: 4
From: Seattle
1992 911 C4, 2008 P2 E63 AMG (gone but not forgotten), 2007 SL65 Renntech
SL65 Transmission hanging
So I know that some AMGs (my E63 did) will keep RPMs high and the transmission in a lower gear if it thinks you are driving aggressively. Since I had my ECU reprogrammed with later version of software my SL65 hangs like this forcing me to use the paddle shifter to upshift and get the RPMs down.
For example...... Yesterday on way home I actually found some open freeway so a went WOT from about 65 MPH to 90 then let off to idle. The car stayed at about 5000 RPM and in the same gear until I upshifted with paddle shifter to 5th.
If you wait and let the car do the upshift it generally lets go like it doesn't want to and the rear end bangs.
Hopefully that all makes sense to someone.
Thoughts?
For example...... Yesterday on way home I actually found some open freeway so a went WOT from about 65 MPH to 90 then let off to idle. The car stayed at about 5000 RPM and in the same gear until I upshifted with paddle shifter to 5th.
If you wait and let the car do the upshift it generally lets go like it doesn't want to and the rear end bangs.
Hopefully that all makes sense to someone.
Thoughts?
Member
Joined: May 2013
Posts: 230
Likes: 27
From: Maryland
MBs: SL55, GLK350
I believe this behavior is due to amg "speedshift" tcu programming and is considered normal operation. I have noticed similar upshift hangs on my sl55 following wot bursts. I've found that the tcu will upshift the trans smooth and quick by just slightly easing into the accelerator for a second instead of full idle on the decel - otherwise it will hang for a bit with aggressive engine braking before a firm upshift or downshift depending in how much speed was lost.
Another way to avoid it is backing off the throttle more smoothly rather than abruptly letting off.
Another way to avoid it is backing off the throttle more smoothly rather than abruptly letting off.
