OK, time for an update. It took me quite a while to find a shop willing/able to do the transmission fluid level check and top up – perils of living in a small town. Even at shops advertising to work on all foreign cars, as soon as I said “Jaguar” and “transmission” in the same sentence, they went blank-face and said no before I even had a chance to explain what I needed.

Finally I found a small, out of the way shop that I had never heard of (and I have been in this town for 50 years). One of the large no-blank-faces referred me to this small shop (after telling me no because they had gotten rid of all their Jaguar/Land Rover diagnostic tools a couple of years ago). I did an online search on the small shop, found they had mostly high ratings for a variety of tasks on a variety of vehicles – a family owned business of many years.

I stopped by the shop with low expectations – they had a hodge-podge of vehicles parked outside of, shall we say, modest premises. Talked to the owner briefly. He said, sure we can do it, we'll hook up your car to our Jaguar diagnostics so that we can do the fluid level check at the required 40 deg-C, etc., etc. I made an appointment for two days hence. Never judge a book by its cover....

I showed up at the shop with my own liter of Lifeguard6 plus two quarts of Mercon SP and left the Jaguar. Two hours later I got a call to come get the car - it is finished. I was told that they needed to add the liter of Lifeguard6 plus most of one quart of Mercon SP. So the advice from the Forum members was indeed spot on. The XKR was indeed low on ATF. I also had contacted the previous owner who had done a DIY transmission service before the sale, and he had averred that perhaps he may have under-done the ATF fill, so even he had suggested a professional ATF level check.

With the transmission now filled to spec, I took the XKR on my usual 20-mile test run, moderately at first, and then flogging it whenever the coast was clear. This time the Transmission Fault message never reappeared, the car did not drop into the limp home mode, even though I was accelerating more enthusiastically than on the previous test runs that had all ended with the one-speed ZF roadshow. Problem solved?

So I now can escape the limp home issue, and the transmission retains full functionality (hurrah), but.....upon hard acceleration, I *think* I heard a “squark” from the transmission at one particular gear change. As the test run went on, that “squark” seemed to diminish in intensity. Perhaps the transmission needs some running time to readjust to a full helping of ATF? I am going to wait for some more test miles before I conclude that I am out of the woods with Herr ZF.

 

ZF tech support in Chicago told me years ago that being 1.5 to 2 quarts low in these 6HP26 units will indeed begin causing performance issues and warning messages....

They also told me that the infamous "squawk" is just an annoying nuisance. It does not damage the clutch packs. I have not experienced the squawk on my wife's 2006 XK8 since we did the most recent Mercon SP drain-and-fill slightly more than 20,000 miles ago....

 

Jon, Thanks for the reassurance. Maybe now I can stop obsessing about the transmission and focus on the other things that seem to be awry with my newly acquired X100. Coming next, the UnCATS XKR...calls for a new thread.....

 

Thanks. I thought maybe you'd found a better method.

It's an extremely clumsy and idiotic method, but let's not forget it wasn't supposed to be. These transmissions were billed as "Lifetime fill." The BMWs even came with a green sticker on the pan stating so. Unfortunately, too many people look that literally.

 

Being a newcomer, I did not realize that my so-named “squark” is actually well-known and officially called the SQUAWK. Thanks to @kstevusa for pointing me in the right direction to useful threads on that topic. Search and you shall find. This forum is a wonderful resource!

 

Lifetime only means "until the day after the warranty expires".

 

Update - after about 60 miles more of driving, it looks like topping up the transmission with 2 qts of ATF really did the trick. No longer do I get the orange Transmission Fault warning, with the transmission dropping into one-speed limp home mode. (Though I have to say, with only one speed available, the XKR is still no slouch on the homeward limp.) I still get the occasional squawk on accelerating downshifts, but it seems to be doing it less. Also, I still throw the P0730 DTC (Gear ratio fault), though the transmission continues to perform normally. I wonder if the squawk triggers that DTC? If the squawk continues, I may try a tube of the transmission magic stuff.

 

You may need to reset the transmission adaptations if you haven't already. Also, check the rear wheel bearings. If the rear wheel bearings are bad, it is known to cause odd transmission codes.

 

Thank you for your response. At the very start of this maybe too long thread, I had already checked the rear wheel bearings via the wiggle/waggle test (at the same time that I did my initial familiarization with lifting the car at the rear using the tire changing gear out of the boot, w/o removing the wheels) - those bearings seemed to be rock-steady.

Based on your other suggestion, I have spent several hours in searching the forum on transmission adaptations topics, especially as they deal with the squawk. There is almost too much information available, spread over many years, and I am struggling to digest it all. To minimize confusion of threads, I will try to start another thread on that topic, hopefully to elicit responses at the level of "transmission adaptations for dummies (2024 version)".

 

It requires dealership-level software known as the Jaguar IDS/SDD software, a special cable to connect to the car, and a Windows XP computer.

 

Maybe this does not apply but I have a foxwell nt530 and it does trans adaption clearing for my 2008 xk. I would assume the same for x100 but check manufacturer to verify.
wj

 

Up until four or five years ago, one relatively local Jaguar dealership still had the hardware / software required to perform the ZF 6HP26 adaptations drive cycle procedure. I had them do it a couple of times on my wife's 2006 XK8 to clear up some minor shift-quality issues she was complaining about at the time. In both cases, the shift quality returned to normal after the procedure was done. In both cases, the service manager charged me $150 for the procedure (which was quite a fair price). The last time was in April 2016 and since that time the shift quality has remained normal. Fortunate for us because that dealership no longer has the hardware / software required to do it....

Search for Jaguar Technical Service Bulletin JTB00145. That bulletin explains the procedure in detail. Perhaps you can find an indie shop that can still do this for you....

 

@wymjym @Jon89 Thank you for your responses re. transmission adaptations.

I have started a new thread on scan tools that *might* relate to the above:
https://www.jaguarforums.com/forum/x...ostics-276164/

The link to the Jaguar TSB on transmission adaptations is:
https://www.justanswer.com/uploads/c...00145NAS11.pdf

I think I will shuffle off to the new scan tools thread to see what pops up....

 

p0730 means a nasty flare is going on, when you get 783 784 785 you're done. probably already smoked the rear stator support and eclutch frictions from running low.

 

So I should start saving my loose couch change for a replacement ZF gearbox…..

 

Not necessarily. Mine did the same after running low for a while. I didn't have the necessary gear to do the adaptations, so I let it do them itself. Eventually, the codes happened less and less until they no longer appeared. Mine was P0783. The box shifts perfectly now.

 

Thanks for the morale boost!

 

Recap:

2006 XKR @ 86k miles. Purchased sight unseen. Arrived with transmission issues: when accelerating very vigorously, gearbox shifts are rough with severe squawks sounding. Transmission Fault light trips on, with gearbox going into single-speed, limp-home mode. But turning off engine and restarting makes the Fault light disappear, and normal gearbox operation is restored. Until return of identical fault at next vigorous acceleration. Repeat....

Then discovered that transmission was low approximately 2 qts of ATF. After transmission filled properly, transmission faults no longer occur, although gearbox still performs much milder squawking. Investigated clearing ZF gearbox adaptations to alleviated squawking. Detoured into the world of hand-held diagnostic tools.

Latest:

Tried to use the Foxwell NT530 to clear the gearbox adaptations. Process may (or may not?) have been successful (see https://www.jaguarforums.com/forum/x...ostics-276164/). Assuming the adaptations had been cleared by the NT530, decided to perform by myself (silly boy) the Jaguar Service ZF Transmission Adaptations Drive Cycle: https://www.justanswer.com/uploads/c...00145NAS11.pdf

That Drive Cycle consists of a series of steps in which the gearbox is constrained to a particular gear, from 2-nd successively to 5-th, up to 50 mph, followed by gently slowing down to a 10 sec standstop. This process is to be repeated three times. The instructions say that the steps can be done in any order, with any arbitrary interruptions between the steps. Hmmmmm.

Looking down at the left-hand side of the J-gate shift control, it occurred to me that I might be able to replicate each step of the Drive Cycle procedure just by using the J-gate to select what gear should be held and for how long. The main question would be: was the IDS ordinarily used by the Jag techs in the Drive Cycle performing any bi-directional control during the drive cycle process? Or was the IDS just being used as a bookkeeper to ensure the completion of the steps? If the latter, I might just be able to replicate the Drive Cycle all by myself..... After a couple of false starts, I was able to replicate the Drive Cycle on our local roads. So: did it make any difference in the performance of my squawkin' ZF?

Well....no. All the above gobbledygook had no impact on the sub-optimal performance of my gearbox. Just as I was wondering what to do next, out of the blue, I received an invitation to use a fully functional WDS (just what the Jaguar dealership in 2006 would have on the shop floor) to diagnose my problems, and, I assume, perform the adaptations clear. I leapt at that. It will be several weeks before I can hook up to that time machine. I will return to share what I learn.

No one promised that a now-18 year old X100 XKR would be easy to live with!

 

Frankly, I don't think an adaptation reset is necessary. The BMW manuals state that a reset is only necessary if you replace the transmission. This may, or may not, apply to Jags. The trans is the same, but I have no idea if the TCM programming is the same. The contemporaneous BMWs do have automatic, manual and sport modes, just like the Jag. So, they're certainly similar.

Anyway, I doubt that doing a reset will change much of anything. I'm happy to be proven wrong.

 

You may be correct. In that case I will next fall back upon the recommendation of @Pistnbroke from very early in this thread (post #3): get two tubes of Dr. Tranny. Already ordered from The Amazoonians.