My dad has a 02 M3, he just got home and said to me that the car is acting as if it is missing a gear or a link and chuging along and not shifting as should, i think it must be the diff. but if anyone else thinks otherwise let me know, he has his 1200 mile check coming up but i wanted to know if anyone else has experianced this issue?:dunno

What leads you to believe its the diff? Can you give us more detail on what the symptoms are?

he said that when he shifts in acceleration that it feels like the rear end hops and almost skips the gear completley, and the shifting is really unpredictable, its a mistery to him and i, he's starting to regret the trade of the porsche for the M, i really hope its nothing serious.

Skips a gear completely? That wouldn't be a problem with the differential. Further, if the car is still moving forward and the gear shifter hasn't moved, there is no physical way for the transmission to skip a gear.

Have you considered turning off the traction control? It sounds as if your father is shifting rather hard, inducing wheel spin as he enters the next gear. When the wheels start spinning, the traction control removes power to regain traction, resulting in the bogging feeling.

I've never heard your problem described, but it definitely doesn't sound like a differential problem.

Bryan may be correct, remembe that ASC/DSC limits throttle and can also apply the brakes on the offending wheels.

How do you all drive your M3? With DSC off and the Sport mode on at all times? I've driven over 1300 miles so far and have yet to turn off DSC or use the sport mode. Am I missing a whole new driving experinece?

You haven't turned on Sport mode even once? Dang, you people have way more self control than I do. I hit the Sport button before I even backed out of the parking space the first time I test drove an M3 at the dealership. I had the DSC off by the time I got out of the parking lot. For normal driving, I'd probably leave the DSC on though.

Have DSC off isn't going to add anything to your driving experience unless you know how to properly handle a car in oversteer situations.

M3 noob here... What is different in sport mode as opposed to... regular mode, I guess?

(deleted question about DSC)

The M3 has a "Drive by wire" throttle, meaning the connection between the pedal and the actual throttle bodies is electronic. Thus, in sport mode, the computer alters the program to make the throttle bodies more responsive to pedal inputs. At least as I understand it.

Dads car is back, it had a bad "coil" and needed to be replaced, im assuming this affected the drive by wire system, thus leading to the problem, so not the diff at all, you were right BMWRacerITS, its all fixed now, gotta lova warranty.