Hi guyz
I was driving my xj8l ds morning and observes the transmission fault message on the dash.. my xj8l does not go past 60 now. Can anyone help with this.

 

Well, only to say you need to get the stored fault code(s) read to see what might be the trouble.

Any rough changes recently ? FWIW I have had this, and a TCM reflash cured it, after some rough changes. As the box wears the changes can get a bit rough, and the fault detection software picks this up and puts tranny and sometimes engine into restricted performance mode.

 

how many miles? Any other symptoms prior to the message? Does it happen after a gear change, or immediately?

 

My wife is out of town and her 2005 XJ8L is giving her the transmission fault light and the car will not shift into higher gears. I am at the mercy of a dealership in San Antonio, TX to figure it out in the morning. What did you find out Adinashena?

 

Hi NDW,
I did not do anything to my XJ8 after I discover it won't go past 60. I parked it at work on that day, after work I started the car the transmission fault message on the dash was no longer there. My XJ8 has been drivig fine since then.... Goodluck with urs..

 

My wife parked the car for the night as it was late at night and the dealership was closed for the day. She started it the next morning and the transmission fault light was not on, and the car drove fine. I still had her take the car to Barrett Motors in San Antonio and get the TCM reflashed. This is the first time I have had that done to the car. The car drove fine for 300 miles home.

We have been experiencing hard shifts periodically for the past 6 months. Maybe this will help with that issue, I will report back in a few months to update on the hard shifting problem. The car just turned 100,000 miles the week of 12/10/12.

 

Hi NDW

It was explained to me at a dealer that the boxes gradually wear very slightly over the life of the car, (this is normal BTW), and this can cause the changes to get a bit rough over time. The changes are invoked by electric valves in the gearbox, controlled by the TCM also in the gearbox.
I got it when it was very hot, and transmission went into limp mode. There is a watchdog that checks change quality by detecting fluid pressures in the change mechanism, and if it detects what it thinks is a rough change will take action to protect the mechanical parts.

Of course this is a damned nuisance to the poor owner when it happens, because there is very little wrong with the car !!

So a TCM reload is done and the TCM in the box is essentially reprogrammed to account for this slight wear, and normal changes are restored. In my case, I had the fluid completely changed this October, and this has also improved the change.
You might consider having the tranny fluid replaced; some say it is beneficial, others disagree. My local independent, (and highly regarded), shop said it would help so I had it done. Doing it properly is NOT cheap !

 

Fraser, thanks for the explanation, that all makes sense. I will get the transmission fluid and filter changed sometime soon. I read the directions for doing it, and it isn't difficult, but it is tedious. I have replaced many transmissions in race cars I own, but they are elementary compared to the nuances of this ZF transmission. From the users standpoint, it appears that they didn't want the user to ever do routine service on it.

Thanks for the explanation.

 

Any transmission control that has to be reprogrammed for normal wear is faulty. I love my Jag but would not buy another because of this nonsense!

 

Well, this gearbox is in use in other European cars, mostly German, so presumably this problem occurs with them as well.

It may, of course, be that the Germans recognise the problem and put a reprogram into the normal maintenance routines so the owner never gets the fault because the regular reprogram stops the fault from occuring in the first place.

 

I'm now equipped with a working SDD and my tranny needs adaption.
But maybe I'm just a coward, but I the idea of flashing the tranny to death keeps me up from doing it.
Did anyone do it himself and could provide some step-by-step procedure ?
( .. how about getting the correct file for flashing ? )

 

nebelfuerst

Have you seen this?

https://www.jaguarforums.com/forum/g...-66558/page11/

 

Yep. But I didn't read anyone that had the tranny flash done himself.
As my dealer is 100km away, I don't want to end up with a dead transmission.
My friend owns a IDS of a different brand of car and this IDS did clear the flash and then reported "file not found"... his TCM was killed this way.
Can this also happen on SDD of JLR ?

 

Start with just clearing the adaptations w/o 'flashing' the TCM with any software. That should be all you need. The learning process after a clearing is very specific, follow it precisely.

 

Hey Matt,

Does the box you have allow you to clear the adaptations and/or reflash the TCM? This might be something that I'd like to do. Maybe I could buy your lunch in exhange for some local know-how? :-)

Kyle

 

Ive cleared my own, but have not attempted any flash update myself. Lunch Is about how long it will take take to complete the process, coincidence? My cable is on loan at the moment, but it should be home in a week or so, send me a PM, im sure i can help ya out.

 

there is nothing wrong with getting the tranny drained and filled. In fact, I encourage it... I'll explain why...

When you DRAIN and fill the tranny, you rejuvenate the overall viscosity of the fluid, it shifts smoother, performs better, etc...

When people take their cars in to get a FLUSH and fill, is when most leave with a problem... Over time, transmissions wear, clutches wear, things wear down, creating particles in the fluid that are not always magnetic, (like clutch friction disks which are glorified paper products) and thus don't get snagged by the magnets placed in many transmissions of today.

The reason FLUSH and fills harm transmissions is because shops hook up these pressurized machines to pump fluid into the trannys, and they essentially blow all those particles and other crap around, and you really don't get rid of the old fluid b/c it is stuck in the valvebody... Then when you get in to drive, you foul your tranny.

FLUSH and fills don't work b/c modern auto trannys have electronically controlled valvebodies. you have to apply electrical power to the valvebodies to get the valves to open and cycle to really "clean" your tranny out.

No shop is capable of doing this. There is no way to truly do it correctly without risking damage to the transmission (i.e. driving the car while it is floating in the air on a lift while the tranny fluid is unable to pressurize its own fluid correctly b/c well, you're servicing it... let me know how that works out for you...)

moral of the story: Drain and fill your trannys as much as you want by dropping the pan. new fluid doesn't hurt anything. (if it's not being pumped in with a barbaric machine)