My '04 XJR shifts from first to second under normal acceleration at about 5 mph. Once it has shifted to second it will not shift back down to first unless I stop. Every other gear downshifts as I would expect it to. If I'm in 5th at 30 mph and stomp the throttle it goes down to second, but at 5 or 10 mph full throttle will not give you first, and of course the J-gate won't give you first.

This isn't much of an issue if you want to accelerate in a straight line, but it is when you're turning. So, the only way to turn out into traffic seems to be to put it in sport mode, which holds first a little longer, turn off the traction control so you can use enough throttle to hold first with some wheelspin and a little fishtailing, then when the car is straightened up go for full throttle. Otherwise you turn out and by the time you're ready for full throttle you're at 1200 rpm in second, and by the time you're turning the motor fast enough to give plenty of boost and power you've either caught up to traffic and need to hit the brakes, or been rear-ended by the dump truck you turned in front of.

Is this normal?

 

Mine is doing the same. Just as you I don't like it - actually really the only thing I do not like about the car. It makes rolling starts very slow - and many times you need the acceleration 1st would give you, but you are stuck in 2nd

 

So it isn't just me. Now the question is, is this normal or do we have the same fault?

I also found a TSB that describes another problem I have:

"Issue: Owners of some 2004 MYXJ range vehicles, equipped with the ZF 6HP26 automatic
transmission, may complain of a driveline clunk/knock when changing from reverse to
drive, or while downshifting from fifth to fourth or second to first when the vehicle is

slowing.

Solution: Install a new automatic transmission extension housing seal and output
flange (see Workshop Manual, section: 307-01, SRO 44.20.18)."

I sometimes have a hard downshift just as I come to a stop.

 

I cannot tell you if it is normal - my dealer says it is normal. I have no clunk but the downshift to 1st as I am coming to a stop can be a little late and hard. If you search for ZF lurch I see similarities - it is just not so bad in my car - but this problem was never solved. I honestly can say that I would prefer if my next car do not have a ZF transmission - because I am not impressed -My Nissan shifts better.

 

I would also appreciate if someone could give an input on this issue - now it is starting to bother me again - thanks gmcgann.
Are other XJ8 owner's here experiencing the gearshift the same way? The dealer told me it is normal -well that was said when the car still was under warranty, but it is the first car I have had that will will not shift down 2nd-1st when you floor it at 10mph - mine has done this since I got it.
Thanks
Martin

 

It definitely makes it tricky, even in a straight line. If the DSC activates even for a moment, the car shifts to second. Turn the DSC off and you have to roll into the throttle to keep the wheelspin down, but roll in a bit to slowly and it shifts.

I'm taking the car to a British Car Show in a couple of weeks and I toyed with the idea of entering it in the autocross, but if I can't get first except for the start, what's the point?

 

I suspect this problem is a feature rather than a bug, and is there to prevent too much torque wrecking the gearbox in 1st gear.

 

The ZF 6HP26 is rated for a maximum input torque of 600 newton metres (443 ft/lbs)torque, while the XJR puts out 540 nm / 399.0 ft/lbs. Besides, how would downshifting into first be any different than starting out at full throttle in first? If this was an intentional behaviour I'd be more inclined to think that Jaguar didn't want the car getting away from someone when they hit the gas.

 

Update:
Last winter I did the transmission fluid/flush and also cleared the adaptations and reflashed the TCM. Since then the car DOES downshift to first. My guess is that the original owner never got on the throttle hard and the transmission "learned" his patterns. Clearing the adaptations may be all that is needed, and/or a reflash.

 

The 2-1 downshift may be blocked if:
-Transmission fluid temp is too high (to cool it down TCM limits a 1 gear, also it engages a TC lockup sooner). Wash a radiators pack, check transmission fluid level and quality.
-MAF readings is incorrect. ECM and TCM can't correctly determine an engine load. Wash or replace a MAF sensor.

 

I have the same observations with a 2008 XJR. I consider it as yet another drivability deficiency and since I consider the Stab Control badly done I blame that as much as the transmission.

e. g. Two days ago I started a left turn. The oncoming car was accelerating more than I expected. So I slapped the throttle to the floor board. Some light acceleration for a second or two (seemed like a long time) then hard acceleration in second gear. Many curses.

I drive in sport mode all the time. I turn off stab control much of the time but not the other day.

 

Try to shift a selector to 5 (or 4 or 3) and you'll have immidiate respond. TCM changes shift pattern if the selector is moved out of "D" position. And you don't need a 5th or 6th gear while not on a freeway.

 

As I said, what I did fixed the problem. I don't know whether it was just clearing the adaptations, or the reflash, but I now get downshifts from 2-1. Since the transmission learns the driving patterns (it "adapts," hence "adatations") it makes sense to me that if the previous owner drove the car in a certain way for 72,000 miles that clearing the memory of these driving patterns allowed it to learn mine.
I've never driven a luxury car where the stability control was subtle. They all just shut the throttle off when the car detects wheelspin. I've been in high-end sports cars where the electronics were designed to keep the car accelerating rather than preventing wheelspin, but no luxury cars.
As for sport mode, all it seems to do is change the shift points, mostly under hard acceleration, which means 99% of the time it isn't doing anything for me except keeping the transmission from shifting to sixth. I tend to use Sport Mode and DSC Off together but if I need to pull out quickly I'd rather have the DSC off than Sport Mode. Having the car drop to first and accelerate quickly without having the throttle immediately disconnect due to wheelspin is much more useful than having it hold first a for another few rpm's.

 

It will go into 6th in Sport Mode ... but only when you engage the Cruise Control.

 

Agreed. When I get a round-tuit, the 'learning' mode wants disabled altogether. Permanently. And the DSC defaulted to OFF - reserved for special surface-condition challenges, if/as/when I damned well ASK for it - rather than defaulted ON.

It is the vehicle's assigned task to remain as consistent and predictable as possible. NOT to respond to the dreams of a designer sitting at a 'puter screen ten years ago and 12 thousand miles away from the challenges of the present instant. He is not on-scene. Neither should his assumptions be.

It is the DRIVER's task to learn his mount, adapt as required to match it to real-time conditions. That is why we call him a 'driver', not a passenger.

Herr Zahnradfabrik? I will be pleased to learn your ways, good, bad, or indifferent. Just do me the courtesy of not changing them.

Give any top driver a car he's never met. Rentals, for example.

Give a 'self learning' transmission and DSC computer a driver they know and love.

Send both out to run the same road - that neither have ever seen. Two lane, not four, through Les Diablerets, the Dolomites, or the Appalachians would be fair. In winter, even.

My money, brethren, is on the driver whose mount is not allowed to second-guess - let alone over-rule - him.

Driver who cannot do their part doesn't need a computer with majority wrong answers. They need to be sitting in the back seat while one who can do drives.

Even 'cubic money' and SERIOUS computers cannot turn a medium eggplant into a competent driver. Jaguar, of all folks, should have known better than to have tried it with half-measures.

 

You have some good points but the fatalities etc have dropped hugely over the years not due to better drivers but these features you mention. That's why they default on.

For driving off the public roads it makes sense to have a special mode for those who want that.

 

do you ever use the J-drive?

 

ABS, yes. DSC? Pure nonsense. First-off, it is disabled at 25 MPH and above. Below 25 MPH is fender-bender turf.

Fatality zone was 35 MPH and up even before air-bags, side impact protection, crush zones, testing for off-axis impacts and a great deal more that has given rise to changes in the overall chassis structure of all manufacturers for greatly improved occupant protection.

DSC is no doubt handy to many for low speed maneuvering on snow and ice. It is a needless distraction to any even semi-competent driver on dry roads.

I don't want it interfering with me even in the wet.

 

Only when setting up for four-wheel drifts to humble some fool in a German tinkertoy. Nipponese baubles I can't be bothered to notice. As with fly manure, they are everywhere, so one just learns to ignore that.

 

Why would you think that DSC is disabled at 25 MPH and above? It doesn't get enabled until around 9 MPH and disabling it again at 25 MPH would be kind of pointless.