My tapping sound is getting louder

Dippypud said:

Also see if it's there when coasting, naughty I know, but it'll be drive train or not, failing that take front prop off, do same --- front on, rear off, do same ...


Narrows your list of culprits ...

Click to expand...

Coasting as in take it out of gear and reengage clutch while moving?

HeywoodFloyd said:

Coasting as in take it out of gear and reengage clutch while moving?

Click to expand...

Coasting as knock it out, listen .... dip clutch, listen .... engage relevant for speed gear and bring it up slow, while listening ...

I might help, it might bring up other things ...

Is it more noticeable when turning at all ?

Last year the clutch went heavy on my 1990 90 [ now 200 TDI ] As clutch had done a good bit I decided to pull the engine to sort an oil leak and change the clutch. Oil leak turned out to be the from the gearbox input shaft [ did the crank seal anyway as it was out ] However the clutch problem was due to the fork having lost one of its paddles distorting the release bearing housing.
Try driving with the diff lock in, if noise goes away problem is with centre diff.

Ok here's an update, after doing several tests this weekend...

Noise is 100% rev related. The higher the revs, the increase in "frequency" of tapping. I.e. in 2nd gear at the top of the rev range it's a "BABABABABABABABABBABABABABABAB" noise, very loud, almost so rapid that it's about to turn into a continuous whine. In 4th gear it's a more "tap tap tap tap tap" noise, with a very noticeable gap between each tap.

If I rest my foot on the clutch pedal while driving along, the noise continues - I have to press the pedal down far enough to be able to actually change gear, for the noise to stop. If I leave my foot on the pedal fully down, the noise stays away, until I bring the pedal back up again, and it comes back, initially a little louder.

If, while rolling, I take it out of gear and continue to roll, and release the clutch - there is no noise at all. If I then disengage the clutch again, put it back in gear, and slowly lift the clutch pedal, the noise comes back as the clutch engages again.

The sound is barely audible when travelling at the "comfortable" speed for the gear chosen with minimal drive from the engine. The sound is still very faint but a little more audible when pushing harder with the engine. The sound is at its loudest and very audible when engine breaking in a rev range at the top of the given gear, for instance, if I approach a small roundabout, drop down into 2nd, and as I lift the clutch pedal, as it engages and we start to "lean" on the gear at very high revs.

The sound is still present when centre diff locked.

In my opinion, all of this rules out any of the drive/prop shafts, or diffs/transfer box, as all of these rotate at a rate that's relative to the speed of the vehicle, rather than being engine rev related. This noise is either coming from:

• something in the gear box, and that something is rotating regardless of what gear is selected, but isn't rotating if either the clutch is disengaged, or no gear is selected

or

• something clutch related, and that something rotates whenever the clutch is engaged only

Thoughts?

Only thing to do is open it up and take a look, it does sound like a clutch/input shaft problem.

Maybe totally unrelated but easy to check, wifes car ahs just started to make a death rattle at idle from clutch/geabox area and all sorts of weird noises when driving, good look around and I have found the front crank damper has become delaminated so effectively two pulleys.
Car is only 6 years old!
Pulley from dealer 250 quid.