I am the proud new owner of an 03 S-type V8 4.2L, I am currently trying to do some maintenance on the car. Changing the transmission fluid, because I have noticed that lately the transmission isn't shifting as it should. I have to let of the throttle sometimes for the RPMs to drop. Any advice would be greatly appreciated! thanks!!

 

Welcome, I am moving your thread off to the S Type Forums , this place is designed for welcoming new members and into
Enjoy your stay and I hope you will fix your issues soon , make sure you also read FAQs

 

Plenty of posts and a FAQ about the ZF, but....... that sounds a bit like what's sometimes a high idle problem - do you get that too?

If so, it's likely an air leak. Much easier and cheaper to investigate. Search will get you posts.

What are the fuel trims like?
Search if you want more info about what/why/etc, try:
fuel trim
elm327

The tranny can't necessarily shift right if the car's not running right

 

Welcome to our world 03jag4.2. Ya have an 03...Def. swap in new ZF fluid and def. read the recent trans fluid threads. It is very important to follow the appropriate steps and if ya can, find a Jag tech to do the job. As for high idle: this may be yer trans experiencing late downshifts (change the fluid) and/or vaccume leaks(s). Check to be sure the top of air filter box is snapped down correctly and look for leaks on hoses. As the Moderator and JagV8 suggests...search this forum for the plethora of threads discussing these possible issues.