2003 4.2 V8 Transmission Problem

[Rees]

Hi All,

I have a 2003 4.2 V8 and recently I have had an odd problem with the gearbox. After about half hours driving with the transmission operating normally in D, I'll pull away from a junction, the transmission will do a very lumpy first upshift. Then no matter how lightly or heavily I press the accelerator the it wont upshift until the engine hits 3500 rpm. From that point 6th and sometimes 5th wont engage.

but, if I move the selector to the other side of the gate to 5, it all operates as normal with 6th locked out as you would expect. Selecting Sport mode makes no difference to the problem.

There are no warning showing on the info display in the clock pack either.

Does anyone have any ideas what may be wrong?

 

Thanks   

[StrayCat]

Hello Rees

I’m sorry to hear about your gearbox problem and hope that my own recent experience might be helpful.

On the first of two 1,500 mile drives my car (also a 4.2 V8) displayed vaguely similar symptoms to what you describe. As with your car, there was no warning in the dash panel until after about 1,000 miles then; ‘Gearbox Fault’. I called into an independent Jaguar garage where they cautioned that it could be the torque converter or, big worry, the gearbox itself. I did not have time for them to investigate properly and took a chance on continuing my journey. Eventually the car went into limp mode but I managed to get home and took it to a local Jaguar specialist.

The gearbox Oil and filter were changed and I was able to set off on a repeat of the previous journey. I mention this because 1,500 miles seems more than enough to determine the garage’s diagnosis was correct and I’ve enjoyed perfectly smooth gearchanges since.

Good luck with yours.  

[Rees]

Thanks James, I was thinking on the fluids line. I had an old 3 speed TH400 auto on a car years ago and that displayed similar shifting problems whan the Oil had had its day. I'll have a look for my nearest indie.