W124 E420 Transmission issue

[guyonabuffalo]

Hi everyone.

Most of my activity here is regarding W123s but I am currently considering buying my friends W124 E420.

It has almost 100K miles, is in great shape and he usually gets everything taken care of right away - so I am confident about regular maintenance.

However; it has recently developed a transmission issue. I have searched this and other forums for a similar problem but it seems most folks have different issues with the 722.3/4

It currently shifts nicely through all gears; however once in top gear and doing 50mph+ I activate the kickdown, the engine seems to rev up but the transmission doesnt drop down for a second or more. There seems to be a substantial lag between kickdown activation (revs going up) and the transmission actually engaging. From the little driving I did in his car, I remember it shifting through all gears quite nicely and shifting down nicely as well. Just the kickdown thing is off. He had both the switch and the cable replaced not too long ago.

Any thoughts?