I have had the car 19 months now, 72,000 miles, 60k when I got it. recently I have been getting Transmission Fault when I push the car hard, the trans sticks in 3rd gear I think. The car still drives fine, the engine will just rev higher on the highway. I can fix it by pulling over, turning the car off and turning it back on.

It only happens when I drive hard, over a time. Flooring it once at a green light wont do it, but multiple hard accelerations will. I can do 1 or 2 100+ mph passes on the highway but if I do it multiple times it pops up. I tried changing the fluid, as I read it should be done at my cars mileage and age, but it didn't help anything. Also, after having done it, the mechanic showed me the old fluid and it looked totally clean.

Driving gently isn't an option, if I wanted a big, comfortable, good looking slow car I'd have gone for something else. Is a rebuild needed or just a reprogramming? Any idea on the cost of the rebuild?

 

Try warming it up, shifting through gears while on a ramp, then checking fluid level with engine running.

 

It may not even be a rebuild, just a fix. Might be wrong fluid level, might be something else, even an engine (or power) fault that upsets the trans.

It's just a fault with your specific car, not something they all do.

 

Hi JTC3400,

I would highly recommend that you have your car scanned with a system capable of reading not only the standard OBDII powertrain codes, but also the proprietary Jaguar network (U), chassis (C) and body (B) codes. This requires either the dealer-level WDS or SDD system, a high-end third-party system like AutoEnginuity with the Jaguar extension, or a specialized scanner like the iCarsoft i930 Jaguar version may possibly be able to read all the codes.

The symptoms you describe sound a lot like Limp Home Mode or Restricted Performance mode, in which the transmission is locked into either 3rd or 5th gear. The fact that you don't have a warning lamp illuminated on the dash is curious.

The problem could be related to low transmission fluid, or fluid leaking into the electrical connector due to a failed seal on the connector sleeve, or it could be an electrical/electronic fault since the Transmission Control Module communicates via CAN with the Engine Control Module, DSC Module, Gear sector/J-gate module, Cruise Control Module, Instrument Cluster, etc.

Here are some references that may be helpful once you know if you have any stored Diagnostic Trouble Codes (DTCs):

2004 X350 Electrical Guide:
http://www.jagrepair.com/images/Elec...al%20Guide.pdf

2004 XJ DTC Summaries (full version):
https://www.google.com/url?sa=t&rct=...03388427,d.cWw

X350 Workshop Manual:
http://www.mediafire.com/download/md...f+contents.pdf
http://www.mediafire.com/download/aa...nformation.pdf
http://www.mediafire.com/download/n3...2.+Chassis.pdf
http://www.mediafire.com/download/9b...Powertrain.pdf
http://www.mediafire.com/download/0i...Electrical.pdf
http://www.mediafire.com/download/4j...+and+Paint.pdf


There is a lot of information about the ZF 6HP26 transmission available on this forum and from ZF and others, such as the BMW and Land Rover and forums.

Note that checking the fluid level is complicated by the fact that there is no dipstick and the fluid must be checked under specific conditions and at a specific temperature. The instructions are in the Powertrain section of the Workshop Manual and also in some threads in this forum.

If no DTCs are stored and the fluid level is correct, it might be worth trying a hard reset, in which you disconnect the negative battery cable and touch it to the positive cable for at least one minute. This will clear certain adaptations. The car may drive strangely for a while, but it will relearn and adapt to your driving style and may resolve your issue.

Another possibility is that the TCM needs to be updated with new firmware. The dealer or an independent Jag specialist with the SDD system can reflash the TCM.

Please keep us informed.

Cheers,

Don

 

And search this forum, several posts about this issue. I have it myself now and then when using the engine to brake, twisty mountain roads, fast accelerate and decel kind of thing.

I had the TCM reflashed and things checked...still does it every once in a while.

 

Thanks for the posts, especially Don. I away from home for a while, in Korea but when I get back to the car I will try all the things you listed.

I know there are other posts on the ZF transmission and I read a bunch of them (As I mentioned I changed out the fluid and had the mechanic read the thread first) but I didnt see a post on my specific issue of the car being fine under normal conditions but faulting in hard driving.