CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

2000 Mercedes ML320: Sudden erratic shifting, power loss

A month ago while driving along the city highway at 65 MPH, the truck started rapidly shifting up and down, it seemed like I have no power but the tach showed revs (I think) and I coasted to a stop. I let the truck idle and poked under the hood but saw nothing obvious. I climbed back in and drove home without incident. Then drove a month without incident… until today, when it did the same thing, then drove fine after stopping.



Any wisdom out there? I thought possibly I was zapped by a microwave after the first incident. Now it happend again… about a 1/2 mile form where it happend initially.

A month back mr_josh suggested replacing the motor mounts to fix a “crunck” noise
when just starting off from a stop. The mounts fixed that.

Since my original post the erratic shifting came back with a vengance, the check engine light lit and the car ran awful.

We replaced the motor mounts, and that fixed everything.

New motor mounts fixed your erratic up-shifting and down-shifting? What’s the connection?