I bought a 83 300CD a couple of months ago. I've had other 123 diesels but this is the first turbo. I didn't like driving this one in town because it was a beast. Slow off the line and then crazy boost coupled with hard shift 1-2, and sloppy slip shifts on 2-3 and 3-4.
Yesterday I adjusted the modulator 3/4 turn clockwise and shifts are firm but not jolting, except 1-2 is a bit hard if accelerating hard, that's okay.
Bowden adjusted to make it shift when it should dependent on acceleration rate.
Now all was good with the tranny shifting but the car was still slow off the line and then turbo blast off a bit over 2000rpm. Not so nice to drive around town. So, today I removed the anti-tamper device on the alda and ended up at 3/4 turns counter clockwise by adjusting and test driving.
Now I don't have to press down as much on the accelerator and it pulls strong right off the line. Turbo boost is barely noticeable unless I'm really accelerating hard, the power is strong but very linear now.
The only thing I noticed is that the shifts are not as firm again. I believe this is because I don't have to press the accelerator down as far to get great acceleration so, the vacuum device at the IP hasn't lowered the vacuum to the modulator as much as when the accelerator had to pressed down farther prior to the alda adustment. I'm sure that 1 or 2 clicks clockwise at the modular adjustment will firm the shifts back to where they should be.
This car is now fast right off the line and all the way to highway speed, very linear acceleration and no longer a beast around town. I burn bio-diesel so now I have power, economy and the car is more environmentally friendly than my 4 cylinder 4 runner. I learned all that I needed to know from all the members on this forum and from visiting one of the members that lives about 2 miles away (Fisherman). Thank you all, guess I can sell the 240D now that I'm happy with the 300CD.