I own a 2000 Jaguar XK8 with 73000 miles, am I doing the right thing in not performing transmision fluid change out as is recommended ?

 

Who told you not to change it?

 

I am sure that nobody on this forum would agree with leaving the fluid. It is now standard good practise to change the fluid, together with the sump filter, at around 50k. I have now purchased my (second) XKR at 75,000 miles and am having this done as we speak. The reasons to do it are to improve longevity and to maintain smooth gearbox behaviour; it is definitely better to over-maintain (if such a thing is possible) than to skimp and under-maintain these sensitive cars.

As Mikey asked, who gave you this bit of stellar advice?

 

Folks often report problems with the 5HP24 of the earlier XK8s. When these problems are allowed to develop, the transmission has to come off the car for an A-drum replacement, so there is significant expense in parts and labor. I do not own this, so I have no direct experience, but the reputed fix for these problems is to install a different valve in the valve body, as a preventative measure:

transgo-pressure-regulator-upgrade-179012/

The point is that for the price of a cheap kit and some labor, the big expenses can be avoided/delayed. This is because the valve body can be removed from the bottom of the transmission, and the rest remains in place mated to the engine so it is "easy" to do.

Since you are asking, I thought you might want to read about this and form your own opinion. The short of it is that these transmission are not to be trusted as "sealed for life" as portrayed in the brochure.

Best of luck, keep us posted.

 

ZF has a replacement valve, also, which I used. While not as fancy as the trans go valve, it works if the valve body is not worn. I believe it was incorporated in later X100 transmissions but I don't know what years. Link below.

http://jagrepair.com/images/AutoRepa...%20ZF5HP24.pdf

 

ZF 5HP24 repair manual recommends fluid replacement every 10 years in the opening pages.

"Important:
The transmission is filled with life-time oil.
The oil does not have to be changed until it has been in use for ten years.
The transmission may only be delivered with the oil type and oil amount specified in the corresponding
parts list documentation (see ELCAT), otherwise there is danger of gearbox failure."

Renewing the fluid will not damage the gearbox. You can renew every time you drive the car and all you will do is waste time, money and fluid.

Not changing the fluid can damage the gearbox at some point.

You must decide the balance between prudence and waste.

bob