Hi--I'm new to the forum & have a perplexing problem. I've owned my 2004 XK8 (automatic) for 6 yrs & noticed almost from the beginning when accelerating quickly I would hear a "whoop" sound which was annoying but didn't affect the performance. I questioned the service mgr who said it was low on transmission fluid, but that fluid can't just be added--it all must be drained & new fluid added for several hundred $$. He also said if I could tolerate the noise, it was not hurting the car. Today it has just a little less that 60k mis on it but now (only on occasion) when I accelerate quickly, the car feels like it first hesitates & the noise is a little like a squeal for a few seconds & then it accelerates normally. My mechanic recommends that I replace the trans fluid, but in order to do that on this yr & model, he must replace the pan, gasket, screws, etc & then put the fluid in & it will now cost $1200! He also suggests that if I don't accelerate quickly unnecessarily, I should be able to drive the car for a few more yrs w/o a problem. Has anyone experienced this before? Any advice would be appreciated as I would like to keep this car for at least 3 more yrs.

 

It is a common problem and typically starts around 100k miles.

The price you have been quoted to correct the problem is too high though, you should be able to find an indi to do it cheaper or do it yourself.

I will be doing it next Monday.

See here how to do it as well as the pitfalls.

 

Your adviser is not entirely full of bull***t but his level is high.

What mileage is the vehicle at? If you are around 80K or above you should consider a full fluid change with a new pan which contains an integral filter, if you have less mileage you could consider just a fluid change the ZF fluid is the recommended one though members have used cheaper options, time to search the forum and soak up the info.
One of the best places for the ZF fluid is The CTSC - ZF parts but it seems to be having a re-construction of the site right now.

Last time I looked the ZF fluid was ~$20/ltr and you need 6/7 for a change.

 

The job isn't too bad if you are handy, but the pan bolts have a bad habit of getting stuck so can be difficult to get out without slotting them and using an air hammer to knock them loose. There is a TSB for using bolts with a larger bit size when replacing them.

The price you were quoted is near double what I paid to have the trans services, including the pan/filter and gasket.

 

A fluid & filter change using genuine parts and fluid should run about $500-$600 at an independent European car service shop. Many dealers will charge you more.

This is due on your transmission (despite the lifetime claims) and will in all likelihood solve the 'whoop' which is a known common problem with the old fluid.

This may cure the hesitation (also a known common problem) and you may be done. If it does not, an adaptation reset and a software update (reflash) of the Transmission Control Module (TCM) should be tried before anything more serious is attempted. This should run maybe another $200-400.

 

Many thanks to Race Diagnostics, Norri, Charlie, & White XKR--so much more info/advice than I ever expected! Thanks so much for your time--I'm glad I
became a newbie member!!

 

The fix for the transmission whoop noise is to add a quart of JLM-21906. The fluid is expensive but it fixes the problem. The service manager that said the fluid level was low & you can't just add fluid is hopefully working at a Jiff Lube now. If the hesitation is still there you may need either the adaptations reset or possibly a coded access.