It's actually not that bad a job to replace a kickdown cable. First you need to jack the car up and support it securely on stands. Drain the transmission fluid and disconnect the dipstick tube from the pan. Remove the pan and you're pretty much there. The kickdown cable attaches to an arm that wants to spring back when you pull on it. You can use vice grips to carefully lock this mechanism while you change the cable. At the top of the transmission the cable has a plastic clip that locks it into the tranny housing. Pop this out with a flat screwdriver and pull the cable out. The cable then attaches to the wheel at the throttle body. Use your Bentley manual procedures to adjust the new one.

I did one on a '92 240 in about an hour. My '84 760 Turbo needs one as well. While you're in there change the transmission filter and get a new pan gasket. Use Brakleen to clean out the tranny pan while it's off, but don't wipe the inside with rags. Start the screws through the pan and gasket while you have the pan on the bench. They'll stay in place and it makes it much easier to reinstall the pan.

Dave