Ever since I purchased my XJS Ive noticed that it shifts a bit hard from 3-4. I'm not sure how the ZF tranny works so I'd like to find a solution. I've decided to finally move on to this issue.

 

First thing I would suggest is to check your trans fluid for condition and level.

 

Transmission was Serviced 6 months ago by the PO. I have receipts for the work performed at the same Mechanic I continue to use for the big stuff

 

OK, but it doesn't hurt to have a look at the trans fluid with your own eyes.

 

I don't know about any one else but I find it a little difficult to determing the fluid level. The fluid seems a bit thin on the stick even I know it is full.
RagJag

 

It's not "burned" or smelly?
What do you mean by "The fluid seems a bit thin on the stick"?
"Hard shifting" can be caused by a low level of transmission fluid.

 

Its fresh red, since I just checked it a month ago. How should I really check the fluid level?

 

You need to have the engine running and up to temperature and cycle through all the gears before checking; the best way is to do it after a run before switching off.
One trick is to carefully lay the end of the dip stick on a piece of kitchen paper and roll it; you should see a definitive line on the paper.

 

I finally got around to checking the fluid level and its fine. Everything checks out and looks good. Part of me was starting to believe that I have transmission wear, but I figured something was up. So here's my fix. The gear selector on my 1994 has a Sports Button which in reality does very little except allow for a quicker kickdown on most occasions but not to be confused for an Overdrive button. My ZF transmission is a 4 speed with 4th essentially being OD. Putting the car in "D" allows the transmission to use all 4 gears when it feels its appropriate to do so. All of this is done to keep RPM's down and MPG's up. This is great except it does make the car feel rather sluggish and loose which is worsened by the hard upshift to 4th(overdrive) So I did a lot of research and then my own testing. The results are amazing. The supplement to my owners manual suggests that I use "3" in the gear selector while on "Winding Roads" . "3" is basically DRIVE without "4th gear" or "Overdrive" AHA! This is what I need. You gotta remember that this car can travel up to 140+MPH with 4 gears. The trick is to let off the gas and then shift to "D" when you reach speeds over 60 MPH. Once it shifts into 4th proceed to gas er' up. I down shift into 3 once I come to about 10mph at a freeway offramp. The manual says I can do it at 80MPH or so I think. So it's not like itll break. Anyway the car feels taught and awake. Like a true sports car. Try it. You cannot harm your ZF transmission by doing this. Its not like you're shifting all day. You're simply using your gear selector as an OD button. Oh yeah no more hard shifts and MPG is still pretty good. Its not like I'm hauling *** all of a sudden. It just feels tighter and more in control around corners and downhills. Thank you. Oh and the Sports button does help once on freeway and a quick kickdown is needed.

 

Brewtech, Did you say you slow to 10 mph on off-ramps? Can't imagine doing that unless the road I am merging onto is stopped.
RagJag

 

What I meant was that I downshift into "3" once the car reaches about 10MPH in order to avoid lots of Engine Braking. You can shift into "3" at any speed below 84MPH I believe. Still I prefer not to do that, I just wait till the car is slowed enough where the shift feels seamless. Sorry bout the confusion