When I'm cruising down a hill in D4 without my foot on the gas the car feels like it is surging forward every 10 feet or so. I cannot feel this when accelerating or even when rolling on a flat road at a slow speed, it seems to be when I'm moving down a hill or cruising fairly fast. The surging forward feeling is kind of like someone is giving the car a push from behind. Not sure how else to describe this, but I'm curious if anyone knows what this could be.

 

Sounds like the transmission is trying to decouple and spin free to increase fuel economy or something. PURE speculation on my part.

 

any more ideas on this one? It's still happening, luckily it hasn't become worse, just concerning.

 

I have the same thing, except only when I first start the car and let it roll at like 20 or so.

I think it means that the tranny is going to ass out,
or my mechanic said that the tranny is having trouble shifting because of my broken motor mounts, either way, just speculation.

 

same here but also on flat road....i don't know why

 

Our transmission is "grade logic." That may have something to do with it. When I'm going down a hill like over 45, or the car is accelerating without putting my foot on the gas, I will notice the transmission drop a gear to compensate for braking. It's very easy to overlook, but if you do listen and watch your RPM you will see it. Maybe you just need to add some fluid. Check your fluid level, smell the fluid to see if it smells burnt. Other than that, you may want to take it some where for a diagnosis.

 

By the way ur describing it though, it sounds exactly like our "grade logic" tranny kicking in. On steep downhill grades it "surges" or downshifts. Basically just saves the brakes.