Which Z4 is the best ?

[bennzwel]

That's a lot for the heads up ! Will keep in mind. Generally manual gearbox is less prone to damage and faults than automatic due to their simpler structure.

But good to know about servicing of DCT and the life span of the clutches .

[nicknaz]

Originally Posted by bennzwel

That's a lot for the heads up ! Will keep in mind. Generally manual gearbox is less prone to damage and faults than automatic due to their simpler structure.

But good to know about servicing of DCT and the life span of the clutches .

It is quite speculative at this point. We had a forum member who posted about a DCT gearbox replacement but his car was heavily modified. Others have posted about leaks. No one on the forums has reported replacement due to wear on a stock car.

A counter argument is that the DCT should be pretty durable because it has a wet clutch design and the computers control the clutch slip, and there is no risk of a "money shift" mechanical overrev or improper launches having occurred on the car because of the computer control. (with the 6MT.. ???? on how the gearbox was treated)

[JR956678]

Originally Posted by nicknaz

A counter argument is that the DCT should be pretty durable because it has a wet clutch design and the computers control the clutch slip, and there is no risk of a "money shift" mechanical overrev or improper launches having occurred on the car because of the computer control. (with the 6MT.. ???? on how the gearbox was treated)

I think that's an excellent point. The computerization of the DCT should protect it from damage that could be inflicted on a manual gearbox & clutch while at the same time generating faults (that may or may not be software glitches). It's sort of a good news / bad news scenario.

I did read one poster (not here) who had his friend at a BMW dealership quote on replacing the clutch on a manual M3 and the clutch packs on a DCT M3 and the price was not all that different - $3400 for the 6MT and $3850 for the DCT. There are also after market suppliers of DCT clutch packs so it seems like you CAN replace the clutch without replacing the entire gearbox.

[nicknaz]

Some threads suggest DCT gearbox is replacement only

https://www.bmwcca.org/forum/index.p...o-repair.5827/
http://www.m3post.com/forums/showthread.php?t=503610

Others claim the clutches will cost between $3k-$4k to replace

http://www.e90post.com/forums/showthread.php?t=346268
http://www.m3post.com/forums/showthread.php?t=631131

I edited my previous post. looks like the DCT is definitely a serviceable gearbox from the quotes being posted and the fact there are aftermarket clutches available

[JR956678]

Originally Posted by nicknaz

Some threads suggest DCT gearbox is replacement only

I had a 2006 E60 M5 with the SMG gearbox. In the first year or two if there was any issue (pretty much anything at all no matter what it was) BMW would have the dealer replace the gearbox, and as a result of that most of us on the forums felt that the SMG was not repairable and we were all thinking that we would be faced with a BIG bill to replace the entire gearbox if anything went wrong out of warranty. It gradually appeared that BMW had been telling dealers to replace entire gearboxes and send the old one back to BMW for analysis instead of taking it apart at the dealership so that BMW could analyze the problem. Later on, problems that used to be addressed by replacement began to be addressed by repair. I wonder if they might have done something similar with the DCT leading posters to believe the DCT couldn't be repaired when in fact it can be, at least to some extent.

Others claim the clutches will cost between $3k-$4k to replace

RealOEM.com does show a part number for the DCT DUAL CLUTCH / DRIVE (28407842841) and some related parts on their website though they don't show a price for it. They also show part numbers for the MECHATRONICS UNIT and the OIL PAN and the OUTPUT FLANGE. They show the entire transmission with clutches (28007585538) for $9,944.87. I also found some 3rd party clutch packs for the DCT.

The same thing is true of the manual gearbox; RealOEM.com shows clutch part numbers and some miscellaneous parts for the gearbox but no internal gearbox parts.

I also am inclined to believe that the clutch assemblies of both the manual and the DCT are replaceable as are some other parts but anything that goes deeper into the gearbox would entail replacing an entire gearbox - whether it be a manual or a DCT.

[jts1981]

I love my 35is! Now with some mods I am enjoying it even more. Coming from manual cars I was a bit hesitant about the dct. But after having it for some time I really enjoy the multiple modes. Traffic doesn't bother me anymore, and comfort mode helps me avoid speeding tickets, lol.

I would add the Navigation, cold weather package, and comfort access are must haves.