Drivetrain Noise

[Pete C]

66 reg 102 SWB 5 speed with 13,000 miles on the clock.

There is a repeatable click from the drivetrain when I transition from overrun to acceleration and vice versa, particularly when driving gently. It definitely happens in 4th and 5th gears, and possibly 3rd too. I can't feel the click, and the noise is best described as sounding like bearings taking up slack. I doubt an inexperienced driver would even notice it.

We have had the van for 9 months, but it didn't get driven much for the first 6 months as we converted it, so the noise may have been there all along, or it may be new.

Anyone got any thoughts ? Do they all do this, and it's nothing to worry about, or is it a known issue ?

All input gratefully received before I take it to the dealer.

Thanks,

Pete

 

[mmi]

In the powertrain a possible source of “a click” is centrifugal pendulums of dual-mass flywheel when moving from a position to opposite position.

A few illustrations of T6 DMF structure in the document "SSP 564 The 2.0 litre TDI engine in the T6 - Design and function" on page 10. The document can be found in downloads section VW T6 Vehicle Information | VW T6 Forum - The Dedicated VW Transporter T6 Forum

The document states that DMF is the same on all variants except the 204PS DSG hence my comments below from a different type of van. Unfortunately I haven’t verified if the DMF really is of same type. Anyways, the working principle should be similar.

The local VW garage hooked a couple of microphones around engine and powertrain when some investigation of very strange rattle and pinging noise was done on my 110kw/150PS DSG 4Motion van.

One of the microphones was on flywheel “casing” as the prime suspect was the DMF (at about 30000 km’s). In similar conditions you describe, lightly applying throttle or slowly taking foot off the throttle "a single click" each way can be heard from DMF, presumably from pendulums movement.

But as you mentioned - not easy to notice over road noise in the cabin. At that level “the click” was considered to be normal by VW. I agreed as it clearly was not the noise we were hunting.

 

[Pete C]

That’s really useful thanks, I had not considered the DMF, but that could be a cause.

I think we will monitor it for a bit to see if it develops in any way.

Pete