It has done 90k miles so the job has been on the cards for this summer. I wonder if it has become urgent though. After a hardish two hour drive and then standing 10 mins at a shop it stuttered a bit on reapplying the accellerator from about 20mph. It definitely felt like gearbox and not engine, like a bit of slip but no racing rpms. All other behaviour normal. Flooring it from 5mph ok. Outdoor temp about 27 - 28C.

Or maybe a simple engine service with new plugs etc.?

 

If you can lift the car a flush and oil change is easy. Be sure you know what kind of transmission you have. I bought a pan and filter only to find out I had a Mercedes trans and needed different parts. I used Shell ATF 134 oil.

A plug change is not difficult either. I like iridium plugs. The old ones looked terrible and I felt the car ran better with the new ones.

 

Assuming this is your 97 XK8, please add to the signature. You are overdue for a fluid/ filter change, and should drain and fill three times since the torque converter does not drain. It would also be wise to to replace the main pressure valve with the newer OEM version or the TransGo version.

 

Thanks guys. Mine is the nas xk8 so ZF trans. (I know the SC uses Mercedes trans.)

I have decided to leave it all to my local specialist, including full flushing procedure for the trans. Too many projects ongoing and I do not want to push this out.

 

I just did mine recently along with the front suspension. Wasn't that big of a deal but was I ever cussing the engineers who can up with the stupid Idea of no dipstick and hide the fill plug behind the exhaust pipe. It was language not suitable for this polite forum.
Mine has 81K on it and I won't call the fluid dirty but it was way more brown than red. I only had symptoms of the hard 2-1 shift when cold and still idling kinda high. That is gone now and shifts even smoother than before. I only did filter and fluid. my .02. TM

 

Per,

Good luck with the ATF and filter change. I had very similar symptoms as yours plus I had hot 4-5 shift problems plus 5-4 rough down shifts esp when going up hill.

Changed out total 7L ATF (2 passes) - using a professional garage’s car lift made the DIY a lot easier. Had to wait until Santosh’s car lift was free and glad I did. Santosh had special DIY tools that helped me avoid skin burns against the hot exhaust next to the ATF filler grub screw.

I would recommend the Transgo PR valve mod (dead cheap) and relatively easy to install... but was scary to me as I’d never worked on the internals of a ZF valve body before. ZF also do a PR valve upgrade as it puts better odds on your side to avoid A Drum failure, a known weakness on the ZF5HP24.

 

There is dialogue that both 'A' drum failure and cracked lower valve bodies are a symptom of the pressure valve malfunction. ZF released a TSB (see attached) that documents the drum failure.

If you do elect to go the Transgo route, member BobRoy has posted an excellent tutorial, which contains additional tips by DonB. I imagine that it will be equally relevant to fitting the updated ZF part:

https://www.jaguarforums.com/forum/x...2/#post1648275

The modifications do not claim to prevent the drum failure, but to reduce it's likelihood. Made it a no-brainer for me.