THE FACTS on my Jaguar. It is a 3.0 automatic 4 door 2002 X type car with 94k miles and a came with professional maintenance records that show no history of problems from a reliable dealership. We drove the car approximately 2,000 miles before the problem started. THE PROBLEM: The car shifts to neutral if you try to rapidly accelerate, but as soon as you lift your foot and let the rpms fall off the gear re-engages flawlessly and you continue without further problem. The car downshifts without problem at any and all speeds in Sport Mode and some of these have been quite excessive during my experimentations (which would seem to me to mean the transmission was correctly handling internal fluid pressures). I have noticed that rapid acceleration in Sports Mode has far fewer drops to neutral than when operating in standard automatic mode. I have changed the motor oil, filter, and the tranny fluid 3 times over a period of 3 weeks (as per instructions in this forum) and driven about 3000 miles without any improvement or deterioration of the condition. There are no problems whatsoever during normal town driving conditions (under 45mph). All gears shift up and down properly. During my tests I have noticed this drop to neutral problem as we hit 2k RPM's during rapid acceleration, but it occurs at any and all speeds when you accelerate quickly. The car functions fine from 0 to 100 mph ( probably further but that's as fast as I ever go) so long as you don't ask it to get there quickly. After repeated or extended drops to neutral I get a " Gearbox Fault" message but the car never goes to safe mode and will continue to drive flawlessly with the gearbox fault light on. When you stop and restart the engine fault is gone. When we hooked an Autozone interpreter to the system it got no fault readings (yes, I know the AZ readers won't read Jag very often). My closing questions are: Besides the transmission what could cause such an issue? Could their be anything in relation to a dirty throttle body that could cause this? Could this be related to a sensor? computer? I'm stumped and as always appreciate the help you get here. I guess it's time to go to the shop with her, but I'd sure like to have the problem more defined so we don't waste hundreds of dollars in diagnostics. I'm just not convinced there is an internal crack inside the tranny. But maybe downshift pressures affect the tranny differently than acceleration pressures.. That's why I'm here asking for help. Thanks guys for whatever you can share.

 

akejama, from my understanding of auto trannies, your problem sounds like it is one of the bands in the tranny is slipping and when that happens, it is like the tranny went into neutral. Hopefully someone else can chime in and give you a bit more detail. Trannies are not my forte. I know enough to be really dangerous.

 

jaguar x type 2002, change o2 sensor won't start.

 

isla: Suggestion - click this link to start a new thread: https://www.jaguarforums.com/forum/n...newthread&f=14

For more information you provide, the better we can help you, for example:
+ Why did you change the O2 sensor?
+ Which O2 sensor did you change (there are 4 - Upstream sensor 1 or Downstream sensor 2, radiator side or firewall side)?
+ Which engine do you have (2.5L, 3.0L, petrol, diesel)?
+ How many miles?
+ How well or poorly did the engine run before you changed the O2 sensor?
+ Is the Check Engine light on? Was it on before you changed the O2 sensor?
+ Were there / are there any error codes, before or after you changed the O2 sensor? (Many auto parts stores will read the codes for free)
+ Does the engine simply not crank / turn-over, or does it crank / turn-over but not start?
+ What noise to you hear under the hood when you attempt to start it? Any clicking or grinding?