Hi
I'm a new member so apologies if this question has already been covered.
I have had a look around the Forum but if I have missed it and you know where the answer might be I would appreciate a pointer.
My problem is transmission "jolting" when moving slowly. If you are slowing down in traffic and nearly come to a halt then press the accelerator gently, there is a hesitation then the car jumps forward as if someone has bumped you from behind.
Is this an expensive fix or can it be cured by some tweaking by the garage. I have heard that the gearbox is controlled by the car's computer which can be software re-programmed.
Anybody experienced this before?

 

Search here on "lurch" and on google "the lurch" to see which if any matches your experiences. The usual fixes are there, too (and yes are a reflash of the computers but must be done correctly).

 

+1 on searching under "lurch". Very well documented issue. Reflash of the software will fix it for some. For others, like me, it never goes away.

 

Thanks for the information. I have done as advised and can see it is well known. I can also see that the problem does not just affect Jags but BMW cars as well with the same gearbox. What is also apparent is the manufacturers reluctance to admit the problem. I have contacted my local dealer and they want £95 to put the car on the diagnostic machine including the software patch. Can't make up my mind whether this is fair as the fault is down to poor design on their part.

 

I have a 2003 also and in my case the lurch has never gone away entirely despite all the dealer fixes. I have learned to modify my driving style to compensate and just live with it.

 

I had my 2003 S reflashed several times over 6 years under the extended warrantie to correct the lurch, and never did succeed in correcting the problem. It seems to go away at times and then returns. My 99 Volvo S80 had the same issue.

 

Thanks for the rather depressing news. It appears that the main cause of the problem is an uneccessary change from 2nd to first at low speeds. The Lurch occurs when the gear changes whilst accelerating. The engine has more than enough power to accelerate in second gear so I would have thought that raising the downshift threshold would be easy in software.
I am due to have the software re-flashed on Friday (28th April). I will let you know how it turns out.

 

They need to do more than reflash.... and must do it properly or it's a waste of time. See the TSB

 

Sorry if I am being a bit dim but "TSB?"

 

TSB is the acronym for Technical Service Bulletin....

 

Dongle, I'm afraid they've got you by the short and curlies. You are going to have to pay, but you should insist they do the reprogram properly, that you expect to get what you're paying for. Demand your money back otherwise.
Manufacturer's attitude to this is deplorable in trying to ignore the problem.
Another dodge might be to slip into neutral when coming to traffic lights etc., then engage D as soon as the lights change. Also try using sportmode. Shouldn't have to do it, but then you will drive a well-engineered luxury car, won't you?
Leedsman shifted into sarcastic drive.

 

If you've had the reflash DO NOT USE SPORT MODE until at least 200 miles of ordinary, mixed driving. See the TSBs and check 200 is the right amount.

 

Well, I have taken the car to the Garage for a diagnostic. Good news and bad news.
I took the mechanic for a test drive and guess what? The bloody car was behaving itself. However, after about 5 minutes it did a lurch so I didn't look a complete twit.
The diagnostic report indicated that there was a problem and the computer was reflashed. I drove the car home afterwards (about 5 miles in heavy stop/start traffic) and no problem! In fact, it was smooth as silk and I could not reproduce the Lurch no matter how hard I tried.
I don't know how long it will last and I did not really warm the gearbox up but it is looking good so far.
That's the good news but here is the bad. When I picked the car up I had long chat with the mechanic and he told me that I have another problem, a Squawk. Apparently whilst cruising if you accellerate hard causing the car to change down to third the gearbox is emitting a noise. I haven't heard this. I went straight home after the garage visit. I will have to look out for it. The mechanic told me this can often be cured by a gearbox oil additive. Worst case scenario is a gearbox rebuild, about £1000. Oh Joy!
This is all such a shame as otherwise the S-Type is a superb car and I love it.

 

It's great reading all about the 'lurch' before taking it in for service. I hope I don't just have to 'live' with it. This post is so helpful guys.

 

F.A.O. Dongle here: You have my rapt attention on this one. I'm pleased you've lost the lurch with a software update, but the "squawk" your mechanic reports interests me greatly. I've often called it the "grunt". It sound like the clutch in the torque converter (it is said to be a 'sliding' clutch) is hunting back and forth at a particular speed at a particular engine load (actually on the same road I travel often). Another odd effect is that the box can sometimes oscillate rapidly between 2nd and 3rd again under very particular load/speed conditions. NONE OF THIS EVER HAPPENS WHEN THE BOX IS COLD! The problems only happen when the box's fluid is fully warm. I conclude from this that the problem is not likely to be software in my case.
This next Wednesday, I'm having the ATF fluid replaced, as far as it is possible to replace, with new and full synthetic that meets the spec. I'm not installing fluid from Jaguar, too expensive. The car has done 120,000miles. All the ATF makers say the absolute max. service life for the best fluid, synthetic, under the best conditions is 120,000Km., or about 75,000miles. I suspect the fluid has never been changed in mine.
Here's the question for you Dongle; Can you find out what this ADDITIVE is you mention that can help with the squawk? Because I'm going to have it installed in mine if I can get it before next Wednesday. If you can do this, you'll have my undying.
Leedsman.

 

Leedsman,

What transmission fluid have you selected?

 

dongle - the TC should still be learning how you drive so don't drive oddly or what do you think it's going to learn!! The various squawks, growls etc are well-known and you can read about them (including potential fixes) using the Search on here and the .co.uk forum.

 

Leedsman
I will try to get the additive information after the weekend.

Thanks all for the driving advice. The garage never mentioned anything about the Sport button. Is it really true that it will wipe the improvements out?
Went out today in the car and drove about 15 miles through country lanes and light town traffic. No problems so far.

 

Thanks for that Dongle; luckily I managed to acquire a tube of "Forte" made additive this Sat., it was an eyebrow-lifting price for a little toothpaste tube size, but Forte have an ironclad reputation among mechanics, so I'm not complaining esp. if it makes a £1000 gearbox rebuild unnecessary. (Forte make their famous diesel injector cleaner, the only one the mechanics say actually works, but it's three or four times the price of others).
Re. software control of the gearbox, I should give your mechanic a call of course, that one who has cured your g/b problems, and ask if use of sport-mode can undo what he has done. If the program changes are to an eeprom, an NV ram, or a flash memory, I wouldn't have thought anything you can do when driving the car can alter the installed program. This kind of program is firmware, and not easily altered. Designers traditionally make sure of this. That doesn't mean to say that subtle sparking in the battery connexions and circuits couldn't do this, but I've never encountered it. In my experience unintended changes have always been to plain and simple good old fashioned rams of the c-mos type, due to the high impedance of gate triggering. Best to err on the side of caution naturally however.
Leedsman.

 

My dealer has re-flashed mine twice. The second time they were very adamant about not using sport mode for at least 200 miles. It is also detailed in the re-flash procedure that has been posted on here. So, sport mode must do something to the adaptive software. The lurch is NOT caused by bad firmware. Hence, the much improved performance that everyone gets from a re-flash. The error lies in the adaptive software. Over time it causes the trans shift points to drift. This is what causes the lurch. Somehow the shift pattern change in sport mode exaggerates this. My issue with it is that the trans is cost prohibitive to service. I can't help but think that there are other issues that get blown off as problems relating to the lurch instead of the trans needing service.