Thanks for the diagnosis and the vote of confidence, Haasman!
Can anyone provide insights into replacing the transmission modulator? (I did a cursory ShopForum search and didn't see any specific instructions.)
Specifically, do I need to drain the torque converter and pan before this R&R? Is it a "plug-and-play" swap, or will special tools be required?
(It looks rather straightforward and simple; but I'd appreciate confirmation of this before I dig-in!)
1991 560SEL-Euro (145,000 miles)
1989 420SEL (Retired at 325,000 miles)