K McCarthy

Hi, I am experiencing a situation where if I press down on the accelerator at highway speed it seems the trans downshifts and rpms increase higher than they should for the speed I'm going and no real pull. It seems to pull well from a stop and shifts through the gears up and down smoothly. The fluid level is full, if not a tiny bit over. Ideas?

machild

You should have the car scanned using MB Star (other scanners can not do all that Star does) to see what is going on with the transmission. Once you have that you will have a strating point as to what needs to be done. Good luck.

chassis

What model year, mileage and which transmission? In which gear does the slipping occur? Does it slip in part throttle or only WOT? What work has been done on the car during the past 12 months?

K McCarthy

The car is 2005, it has 80,000 miles and 722.649 transmission. I actually have the Star tool but not a lot of experience using it.

K McCarthy

The slip seems to appear only during heavy acceleration.

chassis

Which gear, or gears, slip? Please be precise about this. Thanks.

K McCarthy

Hi, I have an update and it's kind of embarrassing. There is no transmission problem, the xentry diagnosis indicated that I had a faulty MAP sensor and the car was running in a protected mode, it felt like slipping because rpms were high but no power. Weird because no "check engine" light. I replaced the sensor and now it is back to it's normal frighteningly fast self.

chassis

Well done. Glad it's sorted.