We discovered this a few months after we got the car. We've had the car for several years now, and It doesn't seem to affect anything mechanically and only occurs under a heavy "foot" which my wife does not do very much.

Anyway, when you step on the gas, sometimes (not everytime) there is a sound made - sounds like a "whoop". Lasts for about a 10th of a second. I have thought it might be a slipping belt - did not think it was the tranny cause there doesn't seem to be any degradation of power. There's no "knocking" like you'd hear with a bad engine mount.

Anyone ever experienced anything like this?

 

Common fault that has been around as long as the gearbox itself.

bob gauff

 

Thanks for the info motorcarman!

I read both of the PDF's. The first one calls for an additive to (I'm assuming) decrease friction. I'm also assuming this will not affect the life of the transmission itself.

The second PDF calls for draining the fluid a total of three times - old fluid once, new fluid twice - and also monitoring the transmission with a diagnostic machine.

The first procedure would seem to be the lesser expensive of the two and a more effective fix. Am I correct in that conclusion?

Would you personally recommend one over the other?

 

The additive is no longer available. I have one unopened bottle. PM if you are interested.

 

just bought a 2006 XK8 with 29K on it and it "whoops" too when down shifting to get on freeway, for example.

Car gets up and goes, so is this just something that just is? I don't care about the noise, just concerned it's a mechanical problem.

Thanks