Sniffer

My 08 CTT has developed a strange sound somewhere in the front end

It only happens under certain conditions - the car has to be cold/sitting for an extended period (i.e. overnight) then once its moving and I start to build RPMs in second gear (around 30kms) I get a weird "clacking" noise (sounds like two gears not quite engaging) - if I throttle up/down it increases/decreases accordingly but if I manually shift up and drop the RPMs it stops and doesn't return until its been sitting for an extended period again

To be clear there is no load on the car or drive chain at this point as the first part of the drive where this happens is on a downhill

I suspect its somehow related to my power steering (Servotronic) as that got real heavy a while back (I know the rack is a common weakness in early generation Cayennes) and from memory the timing kinda matches up to when this sound started

All the fuses are good and the steering fluid level seems fine. I have also looked at the cable connection to the rack (seemed ok) and the Servotronic relay (no way to test as its electronic and not simple contacts) as I know some owners have had these fail but I think I have a deeper mechanical issue with the steering based on the other symptoms

Does this sound like a rack? Or steering pump? Or something else?

RickDC

My girlfriends Toyota Highlander started doing this.. would click from the front end when starting out or after slowing down and releasing the brakes. Whilst maybe not related to yours it may be a first step. What I found was the guideways for the brake pads in the caliper weren't allowing them to move away from the disk properly. I used a Dremel and wire wheel and cleaned out the guide ways on the caliper, greased it with white lithium grease and installed new brake pads. I have a feeling that rust / dirt build up behind the guideways were causing them to catch and movement from speed, brakes and routers were causing the clicking...

Sniffer

Thanks for the pointer but pretty sure its not brake related (they were completely overhauled with new discs, pads and even a new caliper after this noise started)

Coasting or braking don't bring this noise on - once I accelerate beyond a certain point it kicks in like clockwork and disappears the instant I upshift until the next time the car is parked up for a while

nodoors

Power steering pump is generally more of a whine or groan than clacking. If you have not flushed your power steering fluid in a while, it makes sense to get some fresh CHF11s in there as the easiest thing to try first.

So it only happens in 2nd gear before the upshift and doesn't come back again until cold?
What about if you start in 1st gear?