09' BMW M3 Coupe 7-speed automatic DCT gear shifting noise

[dhsieh]

I own a 2009 M3 Coupe with 7-speed DCT and also a 2010 335i Coupe automatic. The ZF-sourced 335i automatic works well in either stop-n-go local traffic or highway driving even though it's not as quick as DCT shifting. However for my M3 DCT, it is rather noisy during gear shifting at low speed. However, high speed driving it's a blast. I took my M3 to 2 different BMW dealers and their master technicians told me that the M3 DCT gear shifting noise is normal since there are hydraulic lifting rods and other parts involved in making the 7-speed automatic DTC from its counter-part DCT manual transmission. One of the technician even told me that I should see how bad it is on older M3's SMG. I wonder if there is any truth to those 2 technician's claims?

[kenwelch]

Originally Posted by dhsieh

I own a 2009 M3 Coupe with 7-speed DCT and also a 2010 335i Coupe automatic. The ZF-sourced 335i automatic works well in either stop-n-go local traffic or highway driving even though it's not as quick as DCT shifting. However for my M3 DCT, it is rather noisy during gear shifting at low speed. However, high speed driving it's a blast. I took my M3 to 2 different BMW dealers and their master technicians told me that the M3 DCT gear shifting noise is normal since there are hydraulic lifting rods and other parts involved in making the 7-speed automatic DTC from its counter-part DCT manual transmission. One of the technician even told me that I should see how bad it is on older M3's SMG. I wonder if there is any truth to those 2 technician's claims?

The DCT will make noises like a manual transmission shifting, because of the shift rails, synchronizer sleeve, and hydraulic actuator system. If you were to sit in a non moving manual transmission car and move the shifter from gear to gear position that would be similar to the sounds that you are hearing. Sometimes shifting into reverse and disengaging the parking pawl will make sounds that are louder with the DCT. These are normal DCT noises.

The automatic transmission in the 335 uses a different shifting method without the extra "fun noises". The inside of the DCT transmission looks and operates similar to a manual transmission with an electro / hydraulic shifting system. If it doesn't make noise....it's not working

Enjoy the fast shifting!!!

Ken Welch
2008 M3 DCT owner
Instructor Automatic Transmissions and Power Train

[VCMpower]

Apples to oranges. The DCT is a manual trans although gear selection is done usually before you click next gear. It anticipates your next move. Hitting the paddles is engaging and disengaging the 2 wet multi clutch packs. The 335i ZF is a automatic fluid driven transmission.

[dhsieh]

Thanks to both kenwelch & VCMpower's replies. it's good to know that my '09 M3 DCT is working fine.