So I purchased my 2008 XK a year and a half ago with 35,000 mi on it. About an hour and a half into my 4-Hour ride home from Maryland to PA in traffic it started to shift hard from 2 to 1 as I would roll to a stop and got progressively worse to where it was the typical lurch and felt like getting bumped from behind.
For weeks I called around to dealers and Indies and searched the internet reading hundreds of threads (I think I've read them all now, jag, bmw, maserati, Audi, all the forms that use these transmissions). Theories include fluid, valve body, torque converter, leaky sleeve, speed sensor, maf, TCM, and software.
As I was leaning towards software (but no dealer was willing to update software on a 2008) I found several threads describing the drive adaptation where the shifting from 0 to 50 is done at certain RPMs for several cycles then rolling to a stop. After following this procedure over five times and every chance I got for weeks, the down shifting from 2 to 1 definitely smoothed out to where there was no lurching but I could feel the shift sometimes. I also noticed that the shifting would smooth out upon more spirited driving and that when the car was cold it was smooth as silk when coming to a stop but after about 20 minutes could feel the two to one downshift occasionally. This made me think it had to do with f trans temp, however and oddly, if I drove an additional 20 minutes or so then that downshifting would smooth out to where I would never feel the shift into first.

It is now at the point after a year and a half and 12,000 MI that there is no harsh downshifting but I can occasionally feel the downshifting from second to first when rolling to a stop but it's only noticeable not hard.
I personally think that it has to do with the communication between the ECM and the TCM that causes this not necessarily the transmission. When I go back and look at the Carfax that came with the car I can see that the first and only owner of the car must have noticed this from about 4,000 MI because of the dealer notes (which finally ended up with replacing the MAF). I really wonder if it has to do with driving style and adaptations being learned.
With that my question is, do most of you feel a slight two to one down shift occasionally depending on conditions or are your shifts completely unnoticeable 100% of the time?

 

My 2014 did it and I found it annoying, try a hard reset and then check if that helps.

It did for me for a while, but getting to the battery as you know is a pita

In the end I got one of these and it resolved things permanently

https://www.diesel-performance.co.uk...m%20your%20car.

Am at 55k miles and my tranny is going in for a fluid service at Nov at a ZF Mastercentre. As they're a 400 mile drive away (a LOT for the UK!) I intend to use it again before the drive back too.

Best of luck.

 

Thanks Marky,

I actually came across that in my early research and was considering it but was hesitant not knowing if it would really work, or worse yet make it worse, so it's nice to know it did indeed work!
I I did change the battery about a month after I bought the car just for good measure but it only took me about 20 minutes so I'm not sure I actually got the hard reset. I do plan on disconnecting it for longer or touching the cables. Thanks!

 

When I drive back from Glasgow to Somerset in Nov after the tranny service and reapplying the tranny tool I will (courtesy of it being early hours) intend to 'boot it' as few popo on the road at 4-9am on a Sunday morning.

Hopefully I can do the 400 miles on a single tank...we shall see

But will have to coast an awful lot

 

I have only 25K km on my 2014 XKR. I changed the transmission fluid at 21K km using OEM Jaguar transmission fluid--13 liters cycled out and in with a filter change. I changed it because the fluid was over 6 years old and the OEM fluid is mineral oil, not synthetic; I wish there was a synthetic alternative. I also changed the ediff at the same time. The transmission is very responsive and shifting from 2 to 1 is very smooth in both "D" and "S". "S" is noticeably quicker.

 

Was the down shift from 2 to 1 noticeable before you changed the fluid and you changed it to smooth it out or did you change it because of age as preventive maintenance?

There are many examples on all different brand forums that use zf adaptive transmissions that experience it from day one. As I said, mine is just occasional now and barely noticeable but I'm really just curious as to whether it's more a feature rather than a symptom. I've read posts on other Jaguar model forums where they took their car in because of the two to one downshift and the car that they were given as a loaner did the same thing.

 

DGL am a little intrigued as to why you changed your tranny fluid well in advance of the ZF recommendation miles/km?

 

Marky - Which unit did you buy. I notice that they have at least two or three different choices that do different things. I'm guessing that you bought the gearbox unit. Is that corrrect?

 

They recommend changing the transmission fluid after a track day.
How you drive it would have a lot to do with it.

That said, right at the period where ZF recommends a transmission fluid change my car did get slightly noisy under specific conditions and downshift.
It went away after dropping it off at Jaguar for a change.
I do "feel" the 1-2" shift if I manually use the paddles and do not have any throttle applied.
No noise, it just fails to auto-rev the engine to match speeds and keep it smooth.

 

I only downshift to 1 at low RPM's. I do this to delay braking and to start from a stop in 1 to get an upshift to 2. I experience no difference from the fluid change. I did the fluid change for preventative maintenance; six year old non-synthetic oil has to suffer some degradation. There's a lot going on in the ZF transmission and I want to ensure I have the best protection. I believe the latest recommendation for changing the fluid is 80K miles or 6 years. Furthermore, the ZF transmission learns as you drive it to adjust to ones driving practice and to the fluid. By changing the fluid with low mileage the change should not be too disruptive to the existing learnt setting. I've read that some people experienced problems after a fluid change and the transmission may have difficulty readjusting. I know the TCM can be reset; however, 6 year old mineral fluid and low mileage gave me a green light IMO.

 

Interesting thread... growing up with manual transmissions, I very rarely downshifted to 1st during the slowing of the car. I typically put the car in first if only starting from an absolute stop. And in greasy weather, started the car rolling many a time from 2nd.

A theme I’ve followed with the paddle shifters.

I do wish we had a ZF shop close by... that would look at passenger cars. (Yes, I’ve tried) . Maintenance and fine tuning of the transmission would be a nice asset.

 

Ralph I bought their holy trinity, so TCU reflash, Pedalbox plus and the Power Control unit, the latter two have bluetooth control and a phone app, most noticeable is when I turn the pedal box off as a lot more pedal pressure is required. That said I rarely drive in higher rev ranges, and having a license clear of points is how I want to keep it

I paid a lot less than their list price as got 45% off on a Black Monday deal, there was actually a glitch on their system as should only have gotten 30% off, but they honoured it

 

I'm always skeptical of these plug-and-play tune mods or chip tunes. So many fake products out there. I bought a Jaguar XKR to enjoy as a sporty GT and not to track it or beat the crap out of it. I bought it to drive it like a GT. I would be more inclined to buy into something like this for a true sports car or an F-type.

 

Perhaps you are right and it's purely placebo in that 'I spent the money so it must make an improvement'.

Am pleased to say I don't fall into that camp...and only a dyno will prove any gains. I have a before so will be taking it for an 'after' following my tranny fluid change, nose coupler and new SC fluid. Hopefully will be able to get the dyno done in Dec or Jan and will remember to post up the results

That said, longer term I am probs going for a remap as already have no backbox, smaller upper pulley and K&N's and the only way these can be factored in is via a custom tune as on the stock tune I was down by 17 horses. I am however loathe to change the cats or the mid section as it is already biblically loud and would pee off my neighbours who are ATM just jealous.

 

That is a heck of a long way to drive (800 mile round trip) to get the fluid in the transmission swapped out. Is there a specific reason you don't want to have this done locally? I admit I know very little about these things, but how hard is it to drain out the old oil and refill with new?

Your car is a lot more economical than mine - there is no way I could even think of doing 400 miles on a tankful of fuel! I think the 5.0 models are more fuel-efficient than the 4.2 models though. With a bit of vigorous driving in Sport mode, I can achieve less than 17 mpg* fairly easily. More economical on a long-distance motorway drive though (eg through France).

* That's our big, hunky British gallon of course, not the smaller, less hunky US version

 

Because I am seeing 'gyaldem' in both Carlisle amd Glasgow on my trip.

Also Mackies transmissions have a stellar record with our cars and are the easiest to get to, the other I believe is in Kent which is hardy as scenic and the wimmin are less grateful...lol

Albeit they do have beards and carry knives north of t'border.

Apologies to anyone Scottish that's in, also any feminists. or married...heck anyone with a beard!

 

Thanks Marky. I am interested in hearing about your before and after dyno results. Ralph

 

Ah, in that case, perfectly understandable. Although, HST, it's a long way to go even for that. Are there no women in your area?

I understand, but come back to my earlier question - how hard can it be to drain the trans oil and refill? I ask because no doubt I will need this done at some point and my plan is to use my local Indie where the car is serviced.

Better just to apologise to *everyone* to be on the safe side...

 

Barnsie, I should explain, I am a man of colour living in what has been called (by social workers) a 'vanilla community' most are surprised my English is better than theirs. I sound quintessentially English and my name is Mark T Morgan, which means I confront racism head on when I first meet peeps I've spoken to on the phone...you can see the shock.

Hey, I'm old and ugly enough to get over it but when my teenage kids have to put up with it I have little patience, examples are

1) My daughter being spat at twice when at school.

2) A boy who's parents had moved from Birmingham ( who was ginger mind...so he should have been used to the persecution) telling my daughter he didn't want to sit next to her in tutor group, his reason 'I don't want to catch slavery Aids'

3) A boy from my daughters tutor holding a piece of rope and asking his friend's if he 'should make a noose to make xxxxxxx my slave for the day'. My son overheard this and body checked the boy into lockers, and whilst I deplore physical violence, I was proud he stood up for his little sister.

The outcome was my son was excluded for 4 days and nothing happened to the other boy

I have dated women from the South West who have told me that I was lovely (I am) but they didn't know how they'd introduce me to their elderly parents.

The only one's that will actually offer me their numbers are those that grew up in 'the MTV generation', and since I could legally have a daughter of 39 I refuse.

In the North and Scotland I am more of a novelty rather than someone to be treated with suspicion.

THAT was the short answer

 

It Isn't but you will still have 30% of your old oil in your TC, Mackies use a ZF approved slow flush technique that gets rid of 99% of the old fluid. This isn't to be confused with standard flushes which can completely **** your tranny (oooeer missus!)