Recently had an M46 transmission put in my 740 turbo wagon. My mechanic and I went over everything, and I have since looked over this site, and everything seems to have been done "by the book". However, I don't have cruise control (which I had with the auto before). My best guess is the M46 overdrive relay -- it's kind of funky for other reasons -- and I am waiting for a replacement.

But in anticipation of further disappointment (especially in the vicinity of my right heel on long interstate runs) I am wondering if anyone knows of anything else peculiar about this sort of conversion that we need to be thinking about -- such as a quirk of the 1992 ECU (which I don't think is the problem, but you never know).

All the wiring and connections check out, but the cruise control isn't getting any speed indication -- and as I said earlier it was working fine before, so I don't think any of its various components is the culprit.

For what it's worth the car, although originally a plain jane 1992, now has a 1993 940 drive train (though the relay board is the original 1992 740), and the transmission is out of a 240 of indeterminate vintage (it has a cast-iron case if that's a clue). Don't know which overdrive unit it has, but the overdrive works fine anyway.

And incidentally, if anyone is thinking of this conversion I strongly recommend it, creature comfort glitches aside. However much power and torque the mushbox was actually consuming, my highly subjective assessment is about 50% more go, and the car is behaving the way Europeans would expect it to.

Thanks and any thoughts would be much appreciated.