Truck moving at rocket speed in reverse w/o pressing accelerator

Autos usually have R1 and R2. Might want to use manual mode and be sure it's in R1. Also it might be an issue with "urge to go." If your truck is equipped with that.

 

Sorry. It's urge to move. It's Eaton transmission.

 

This is a characteristic of the freightliner automatics. They're garbage. I'm driving one now and it's either brake or excelerator, nothing in between, no feathering either pedal. You end up slamming into docks and hooking up to a trailer. Where I work, they tell their drivers it's something they're doing wrong and these drivers believe it.

 

These DT12 equipped trucks are full of surprises . )))) I have heard about thuis issue but never seen it in my life.
Go to dealer

 

OP if you have DL i can tell you where to go and what to check. DL means diagnosticlink. Its a software