Someone else trying to work out why it only affects certain gears .
So question what does a DMF do, the purpose is to absorb some vibrations and "smoothen the ride", now imagine roughly 2 plates with a rubber mount (really sketchy) in between.
What is acceptable or does not appear with standard torque can be upset by the higher torque figures of the Remapped cars.
Then the question why does it appear only in 3rd, well that's the toughest one, could be that in that gear the transient of speeds are very large, this is being used on very low rpm till full tilt with every kind of accelerator input in between add some resonance in the system and voilĂ .
Conclusion : if 1 element in the equation is not perfect you could develop the judder, not all cars have equal mechanical elements and not all people are as sensitive, and big torque figures will emphasize it.
When the 911 went to DMF and the 3.6 engine a while back they also had that kind of trouble further emphasized by faulty design of the DMF back then.
So all cars are exposed to it some more than others.
Absolute cure for the diehard is mounting a transit SMF, you won't have it, but will develop other ride problems but at least standstill starts won't be a problem in the long run.
For the record, I know of a very aggressive driver, has done 55000 on the DMF before it failed, and still I don't think a lot drive like him, and he has something like 490 Nm of his Mondeo !! So he is really pushing the envelope.
Posted Mar 16, 2010 (14 years ago)