Hi, I have a 36k car that looks like new. I've posted before about my problems with this 03 E500's gearbox. It was changed under extended warranty, and has always had a noise - probably associated with the torque converter lock-up mechanism.

The torque converter was changed for the second time shortly after the refurbished box was put in. So, two new TCs in a few months, but it didn't help.

Recently, a new 'black box' was put in . . . a $700 part, flown in from Stuttgart. FOC. I thought the noise changed, but never really went away.

First question: On a Caddy, to check the lock's working, you put your foot on the gas and the brake at the same time. This should show a small increase in RPM. How can I check this on the MB? Right now, doing this shows nothing.

Secodnly: Has anyone else experienced a vibrating noise during the 1400 - 2100 rpm range? Gentle acceleration makes it stand out more.

This noise can sound like it's coming from the rear - I'm told this is because it's traveling down the prop-shaft.

In all other respects, the box is behaving well.