High speed slamming into lower gear

[MrCincinnati]

I had this happen on our most recent road trip with my ‘20. Exactly as described above. I assumed my abrupt acceleration caught the nannies off guard and something failsafed.

 

[smurfslayer]

My best recollection is it happened as I applied heavy acceleration in heavy traffic with 3 or more lanes. I was wondering if the collision avoidance didn't like that I was accelerating aggressively while closing in on another vehicle I was going to go around?

hmm... That’s interesting. I’ve got a 2017 but had an interesting scenario where I captured video of the truck decelerating / chopping throttle during a collision alert. If I understand that system from the manual it ‘pre-loads’ the braking system, but doesn’t automatically brake (unless you’re in cruise control with ACC turned on- I was not). I was moving along around 60 when a guy from the left lane cut me off to make an exit ramp. I had tons of room so I powered up and moved left but could definitely feel the truck ‘drop anchor’ for a moment.

With ACC the issue would be amplified by the truck actively braking.

 

[CptMorgan]

This just happened to me today on the way to work. Highway cruise. Sport mode. Mashed the throttle to pass a slow car and the transmission sounded like it dropped from the truck. HUGE clunk downshift. Scared the hell out of me.

 

[ayoustin]

hmm... That’s interesting. I’ve got a 2017 but had an interesting scenario where I captured video of the truck decelerating / chopping throttle during a collision alert. If I understand that system from the manual it ‘pre-loads’ the braking system, but doesn’t automatically brake (unless you’re in cruise control with ACC turned on- I was not). I was moving along around 60 when a guy from the left lane cut me off to make an exit ramp. I had tons of room so I powered up and moved left but could definitely feel the truck ‘drop anchor’ for a moment.

With ACC the issue would be amplified by the truck actively braking.

The pre collision system has its own automated braking procedure. I found that out driving my truck home from purchase when some guy cut me off and slammed on his brakes since we were approaching stopped traffic. If I wasn't paying attention it would've been nice, but I was and the auto braking was pretty unexpected. It can be turned off in the menus. I turned off the auto braking, now it just alerts me for pre-collision.

 

[Jelg2000]

This has happened to me several times. I was able to recreate it on a road trip a few weeks ago. 60-70 mph with an abrupt pedal motion and it'll slam from 10th to 6th. What's concerning is how sharp the shift is. The dealership reset the TCM a week ago when they were replacing the short block, but that's another story. So far I haven't felt the need to try and recreate the shift problem. I'm waiting to get a 1000 miles on the motor before I do so.