2002 325i pulls unevenly

[Michael K]

I'm experiencing a strange problem for (I guess) 5,000 km now. Car is 2002 BMW 325i, 66,000 km on the counter. What's tricky is the transmission - it's SMG. For those who do not know, it's a manual gearbox + clutch, both connected to a hydraulic system that controlls the gear change. So you have only two pedals, like in a regular automatic, and gear changes are done with paddles at the steering wheel or through impulses at the gear change knob.

Good - so now to the problem. Whenever I make a gear change the first two seconds of acceleration are doen in an *uneven* fashion - that is, during those seconds I experience something like a slight shudder, or like a slight hesitations. What could that be? Sign of a worn clutch? The guibo?

What should be noted (mostly my guess): due to the SMG mechanism, gear changes at high RPMs are done *very* quickly (that's the lovely part of an SMG, the rest are downsides...) and so for example when you change at 5000+ you experience real kicks in the seat - my guess is that such a system stresses the clutch and other transmission components quite heavily. The car is driven 1/4 of the time with under 4000 changes, the other 3/4 with over 4000 RPM changes (out of these 3/4, 80% are over 5000).

My hopes of meeting folks with SMG and similar problems (and hopefuly solved!) are minimal. However, did/does anybody with a regular manual gearbox experience such acceleration problems? Maybe we can make a connection...

Thanks a lot guys!

P.S. The dealer does not seem to be very qualified at finding this problem. Recently he stated that headlight covers can't be changed (mine were badly blurred by high speed driving - dust and small stones etc) but I managed to change them by myself - so go figure how BMW is authorizing dealers! It's a real shame for such a highly regarded brand (or *was* it?).

Mike.

[Michael K]

Forgot to mention something that might be important: when the car warms up, the problem apparently goes away.

I'm experiencing a strange problem for (I guess) 5,000 km now. Car is 2002 BMW 325i, 66,000 km on the counter. What's tricky is the transmission - it's SMG. For those who do not know, it's a manual gearbox + clutch, both connected to a hydraulic system that controlls the gear change. So you have only two pedals, like in a regular automatic, and gear changes are done with paddles at the steering wheel or through impulses at the gear change knob.

Good - so now to the problem. Whenever I make a gear change the first two seconds of acceleration are doen in an *uneven* fashion - that is, during those seconds I experience something like a slight shudder, or like a slight hesitations. What could that be? Sign of a worn clutch? The guibo?

What should be noted (mostly my guess): due to the SMG mechanism, gear changes at high RPMs are done *very* quickly (that's the lovely part of an SMG, the rest are downsides...) and so for example when you change at 5000+ you experience real kicks in the seat - my guess is that such a system stresses the clutch and other transmission components quite heavily. The car is driven 1/4 of the time with under 4000 changes, the other 3/4 with over 4000 RPM changes (out of these 3/4, 80% are over 5000).

My hopes of meeting folks with SMG and similar problems (and hopefuly solved!) are minimal. However, did/does anybody with a regular manual gearbox experience such acceleration problems? Maybe we can make a connection...

Thanks a lot guys!

P.S. The dealer does not seem to be very qualified at finding this problem. Recently he stated that headlight covers can't be changed (mine were badly blurred by high speed driving - dust and small stones etc) but I managed to change them by myself - so go figure how BMW is authorizing dealers! It's a real shame for such a highly regarded brand (or *was* it?).

Mike.