A while back I posted a help request for my 04 XJ8 not going into overdrive at highway speeds. I remembered at some point reading (God knows where) that the Jaguars are potentially sensitive to the front wheels/tires not being the same or having the same air pressure thus telling the computer that the car is cornering and would not let the trans shift. So I know I have the same tires and wheels on the car so I check the air pressure and they are dead on equal. I then remember that I rotated in my spare tire with better tread on it. So I check the tread depth left to right. LF 8/32nds and RF 5/32nds. So I rotate the LF tire with the LR tire with 5/32nds tread and amazingly the car has shifted perfect since. I can't believe 3/32nds tread depth is enough to mess with the computer settings. Anyway I hope at some point this helps someone else.

 

well, that is rather unusual. Please let us know if you find any reason that contradicts your theory.

 

Hi Blake i do not even know how to thank you enough. MY right front tire on my 2004 XJ8 needed replacing and i did so. So after a few days i got the car back i noticed on highway when i would accelerate a little bit to change lanes it would not shift back down to over drive. I was very scared by this because i thought my transmission was going. So i brought it to mechanic and they couldnt find any codes no lights on or anything. So the car continued this for 2 weeks then i decided to look this up online and i found what you wrote. Boy did this help me the next day i took my car to my mechanic and rotated the back tires wich have equal tread to the front and the new tire on back and the car went back to complete normal. You are a true life saver thanks again!!!!!!!!!!!!!

 

My cat

 

 

Dang. Who would have thunk?