I'm having some issues with the shifter on my '97 XK8 coupe, and from reading this forum and others, I think I've narrowed it down to the linear switch and/or the neutral safety switch.

Symptoms:

• The sport mode switch isn't working. Press it up and down, no red LED, no apparent change in shift points or performance.
• Trying to direct (or 'manual') shift gears doesn't work. There is muddiness in selecting the gears, and within a few seconds, I get a gearbox fault.
• Last night, my car wouldn't start, despite a fully charged battery. Shifting from neutral, back to park, back to neutral, back to park, finally allowed me to start.

My first question pertains to the neutral safety switch. Is it part of the linear switch or a separate component?

The second question is for the linear switch. I can't find a replacement unit for the '97. I've read it can often be fixed by 'cleaning' or refurbishment, but what exactly needs to be cleaned, resoldered, or adjusted isn't clear. Can I get some guidance on this from someone who has been down this road?

Thanks in advance!

 

First your transmission does not have a dual linear switch for the transmission. That is only used on the Supercharged cars with the Mercedes transmission.
The ZF in the XK8 uses a rotary switch that is driven by the shift cable.
I have attached pictures of the rotary switch and location as well as a shift sequence explanation.
Park, neutral and drive are hardwired directly to the TCM (Transmission Control Module are activated by micro switches on the J-Gate.
Manual is controlled by the rotary switch and shift cable thru the TCM.
I would recommend doing a youtube video search for XK8 shifter. Reverend Sam a forum member has an excellent video for removing the covers for access. Then I would clean everything good with electronic cleaner and check for the indicators lighting when in the gear position.
Next go to JagRepair.com - Jaguar Repair Information Resource another members website and download the XK8 Tech manual second edition 1999 and follow the steps to adjust the shift cable. The muddiness is probably caused by the lack of use and the cable stretch of always shifting to just drive.
Last but not least while you have the Sport button out check it with a multi-meter for on/off function. You will probably find it is no longer working.

 

Exactly what I was looking for, Vern! This will be my weekend project. I'll report back with the results.

 

As above./ On the early cars, there are microswitches in the J gate - two on this little bracket :




And one on its own. The little metal actuators can get worn and fall off which may lead to some of the symptoms you describe. This bracket is available new - I got mine from S N G Barratt.

 

Well, now I’ve done it. Bad to worse.

I removed the console, cleaned all the electrical connections, then I adjusted the shifter cable. I think I messed something up. Now the car won’t start at all. It just cranks and cranks until the lights start to dim.

Now I get a message for Gearbox Fault and Engine Fault. Any ideas?

 

See if this information helps. Your situation is different than mine but my information with links might help you troubleshoot yours.

Link JagRepair.com - Jaguar Repair Information Resource

 

Update... I retraced my steps, readjusted everything, and now the car does start! I'm guessing poor adjustment was not selecting the right position in the transmission? Automatic transmissions aren't something I'm terribly familiar with.

That said, I'm still having the same problem with "muddiness" in the shifter. P, R, N, and D all feel pretty positive, as does 4th and maybe 3rd. But when I shift into 2nd, there's a lot of play. And when I shift back up to 3rd, Gearbox Fault. I don't think my adjustment is anywhere near right. I'm not exactly sure where the cable sheath locknuts are supposed to be. Do I want it as tight as possible in neutral without pulling it into drive?

Vern also mentioned indicators lighting when selecting gears. I've only owned the car about 6 months, but I've never seen anything light up. That's still the case now. Are the P, R, N, D, etc. supposed to light up somehow when they're selected?

 

Yes the position has a light beside it and lights up when in position. Hard to see in the day light but prominent at night. It might be time for a fluid servicing and while you are at it check the electrical plug to make sure it is not contaminated with fluid. That will also cause trans faults.

 

Looks like we have the problem at least provisionally fixed. I had a sleep on it, then woke up with a better understanding of the mechanism.

What I ended up doing was loosen up the locknuts again and pull the cable as much as possible toward the rear of the vehicle without pulling the shifter out of neutral and into drive. Shifting is now much more positive and "manual" shifting now works without going into Gearbox Fault. So far, I also haven't had any issues with the car not turning over. I have developed a hard start issue, but that may be unrelated.

I haven't fixed the Sport Mode button. Vern, you mentioned testing it with a multimeter, but I'm not certain how to test it. If I recall correctly, there were six pins on the switch. Where do I need to stick the probes to test on/off?

 

Doesn't work - too fat at top but useful tool elsewhere nevertheless.

Tip is cut in half here, tape down on a board before cutting or it will fly off somewhere never to be seen again...