I have a 98 CLK320. In the past I heard (I think through this site) that MB has updated the software for the automatic transmission, but my dealer always says he has no such record. Has anything been done to improve the shifting or specifically the lag in downshift? If so, how can I help the dealer find it?

On the 96 and 97 722.6 trannys, they had some problems and were correcting them with the softare and valve body updates. I have not heard of this with the CLK.

Doc?

This is 100% true!!! Yes there is a sofware update for the transmission. My 98 CLK 320 exhibited some jerkiness when starting out in first and also when slowing down to a stop. I'll have to admit that it was very difficult trying to explain the problems but the dealer kept the car overnight to try to duplicate the problem and agreed to update the software in the transmission control module and also changed the valve body if I'm not mistaken.

Now the car drives much better! Upshifts and downshifts seem much more responsive and the tranny also "adapts" much better.

MBNA recently released a 722.6 service summary pack detailing problems, corresponding symptoms and fault codes, and service solutions (both hard and software). There is a software upgrade available for your vehicle. Check with your dealer again; he should have this summary pack.