Strange Noise Under Car

[CosmosC4S]

I've been hearing this strange noise under the car, but it's only happened like 3 times in the last several months since I first heard it.

The noise sounds like it's somewhere right behind me and under the car. Seems to be in front of the engine area.

It doesn't sound like the engine, more like the transmission or driveshaft.

To describe it...Sounds like "a chain slipping off a sprocket"...or gears slipping?

Or like the sound when you accidentally shift into Reverse when you've moving forward, except it's not that harsh.

It lasts only a second, then it's gone and I'll never hear it again in a long time - weeks, or months before the next occurence.

Has always happened when I'm accelerating slow and gentle, like moving off from the lights.

Gives me the feeling that the car is moving in a higher gear than it's supposed to be, then as it downshifts, there's the split second grinding noise.

Or it could be the noise first, then the downshift...I can't be sure as I've not had the chance or enough time to really analyse it when it happened.

I tried to intentionally replicate the noise, by moving at higher gear, but it doesn't happen.

It also doesn't happen when I'm accelerating hard or downshifting aggressively.

Other than those few rare occurences, the transmission and everything else run very smooth.

Has anyone experienced this before? I'm thinking it could be early signs that I need a transmission service?

I sure hope it's not the transmission going bad... :unsure:

It's a Tiptronic 2002 C4S @ 80600miles

Thanks.

[2000996]

A dead cat?