Excessive vibration at idle in Drive with foot on brake

Jaymarks
Jaymarks
New Member
My 2015 jetta tdi has excessive vibration in the cabin at idle in drive with my foot on the brake. It is worse when warmed up. In park/neutral it idles smoothly and nothing is felt in the cabin. My dealer just tells me "it's normal, tdi's vibrate a lot". He has no tdi's in stock to compare. My 2009 that I drove for 240000 miles was always smooth in the cabin when idling in drive with the brake applied. I drove a 2015 Golf TDI yesterday at a used car lot and it was smooth like it should be also. One thing with this 2015 is when I let off the brake, it responds pretty much immediately with movement where as my 09 had quite a delay. To my knowledge, when in drive and stopped with foot on the brake, first gear is engaged and some pressure is applied to the first gear clutch to preload it to the "bite" point. When I shift between N and D, the tach needle does not move one bit, stays steady at 800, so it can't be much preload or it would drag down rpm a little. I have read many threads on motor mounts but it is perfect in P or N and in D the motor sees no load because the tach doesn't budge, so I'm thinking no way it's the mounts. Anyone know if this preload pressure on clutch can be adjusted with vagcom or even measured so I can compare with other people's? This vibration is not normal, it's more like a deep resonating sound shaking the whole cabin that is only present when stopped in gear. As soon as brake is released it goes away and the car moves. It is not one of the many rattles that these cars have, I've corrected some of those. There shouldn't be much difference between P and D with foot on the brake and there is.

You could try doing the clutch adaptation routine with a scan tool, not sure how or why that would be off, but your very good description sort of makes it sound like the 1-3-5 clutch is dragging a bit for some reason.

More info on that can be found here:

http://wiki.ross-tech.com/wiki/index.php/6-Speed_Direct_Shift_Gearbox_(DSG/02E)

I will look into this, thank you. Is that something that is only manually initiated, or is supposed to happen automatically over time?

I just checked out the info on that page, I'll go through the procedure this evening and see if it changes anything. Will report back.

Like pretty much all modern automatics, the learned values are to accommodate normal friction surface wear over time, so that the driver's comfort and the behavior of the transmission remains satisfactory.

When the car is first "born", all these values are set, but everything is new, so there isn't a whole lot of variation. It *should* only be needed to be reset if some repair is made, a component replaced, etc. But in many cases, these values need a little "nudge" to get back to a better base line within the confines of what they are controlling. Electronics and mechanicals and hydraulics are often not the best of friends.

The 02E has matured over the last 15 years since its debut, and has enjoyed vastly improved characteristics, but could still sometimes get wonky. There could also be something not right, but beyond the M-unit's ability to cover, or beyond its ability to actually know.

More helpful info on the DSG:

http://www.evosoft.dk/diagrams/DSG_02E.pdf

Worth a read, even if it is to just help better understand how it works, and how cool it really is.

I performed the entire calibration procedure. Wasn't sure what software version I have but assumed it was above 800. Everything seems the same, it may shift different but I can't tell. Vibration is unchanged. I mentioned that the engine rpm doesn't change when switching between N and D but it does if monitored with vcds or torque app. It idles at 830 but momentarily dips to 805 when put in D. Anyone that can monitor their idle rpm when shifting from N to D to see how much the rpm drop is for comparison would be helpful. This isn't visible with the tach.

If motor mounts have been ruled out, what about a wonky/failing DMF?

The thing is, is is so smooth in N or P. In D, it still turns steady at the same 830rpm after the initial dip. In P or D, the dmf spins steady at 830rpm but it only vibrates in D. (In D the clutch has a slight pressure applied and I think it's biting enough to cause the shake)

When you let off the brake in your car, with no throttle, how quick does your car move?

After a short delay (annoying, but a separate discussion), and as long as I'm on level ground it will idle away to near about 5mph. No shaking or vibration.