What would cause an '06 MCSa (with about 1,100 miles on the odometer) to rev high (to about between 2800-3000 RPM) after each successive downshift on its own?

My drive to work is only 8 miles. It was about 65 F and drizzly this morning. I'd be driving on a straight road at around 60 MPH and I would assume the transmission was in 5th gear at the time (it's an MCSa and I was letting the car do all the shifting). As I'd gradually slow down to a stop light, the car would automatically downshift through the gears as my speed decreased, but precisely at each automatic downshift, the car would quickly rev-up real high and stay that way for a couple/few seconds, then go down, then downshift, then rev up again, etc. until stopped, where it would idle normally. When I say real high, I mean relative to its normal behavior...which is very smooth downshifts, barely able to feel them.

Hmmmm... maybe the tranny just wasn't warmed up enough or something...although it's never done this before.

rock on,

-boognish

 

Were you also going down a hill? That might explain the rise in revs as the car downshifted.

 

Going down a hill.... hmmm.... yea actually it was a slight decline all the way to the stoplight. Does the MCSa have some sort of hill-sensor?

 

Yep, it sure does. If you're braking and going down a hill, the MCSa will downshift to assist the braking...mine does it every day on the same stretch, so I'd say what you're seeing is normal.

 

I love that feature - engine braking

 

Mine downshifts everyday on the same hill. However, I'm not braking at the time.

I'm confused.

 

You don't even touch the brake pedal?
Get someone to make sure you don't have a brake switch fault giving brake lights on all the time ...