Well the good time seem to be over? Driving the 97 XK8 today. Been running fine. No signs of any issues. drove with the same power I have felt since I got it. Kick it in and it took off as it always had, strong, etc.
Well go to doc. Come back out an hour later and put it into drive and in a sec of time, I noticed car wasn't moving with ease and the GEARBOX FAULT flashed up and the CEL came on. The GB DEFAULT went away and has not came back but the car, runs smooth, not missing or anything, has seemed to have lost a lot of its power. It you get on it it will tach up as it should but will not have the pull it should have and it will hang in that high RPM much longer then normal. Seems like the trans is slipping. It drives fine, but seems like it lost 50 HP. Normal driving the motor does not tach out going into other gears as if it is slipping (shifts through all the gears) but if I gas it any decent amount it does not take off and when it goes to shift it will hang at the high end of shift longer then usual with not sense of more power from car. Had it is the garage with Tract Control on, and in reverse with some brake on the tires would let go, the tract control never kicked in.

Seems to me the trans is done? But why the CEL all of the sudden?

 

it shifts thru the gears fine, just a lot less power and if I get on it some when it goes to next gear it revs/holds rev way too long before going to next gear. Over all power of car is waaay down. But just drive it normal and it shifts as it should, no gears missing but just the power is gone. If I put on that button for sport driving, it really does not work. I also can use the FAKE shifting thingy with the shifter but much less power and as I said it I push it I can feel slipping and the CEL for what ever reason.

 

I feel for you. Maybe your thread title says it all - ".../CEL now..." maybe means "SELL now". I couldn't help but notice the irony.

 

Well it is the wifes car, it would have to be ripped from her dead hands to get rid of it.
I just can't believe it is a trans that is just going out, clutches, what ever. To drive fine, then come out an hour later and now what I explain is happening. Something that talks to something on the car ain't liking what it is hearing. Ha ha ha

 

Well. Car parked in garage last ngiht. Get into it today. Still have CEL light. Start driving and it is driving NORMAL again. Driving like had been since we got it. No GB Default error (which only popped up for a few sec the one time it did it). Drove to work, ran fine, normal power, etc. Shifted normal. Stopped at store, came back out and started it and the CEL was gone.
WHAT THE HELL?????????????????
I have to assume the CEL will shed light on some of the issue and the GB fault error will also leave a code behind for my shop to get an idea what happened???

 

well been driving the car off and on today. No warnings, no cel, running like normal again. WTF? Sensor gone wild for a bit?

 

Code will still be stored, you should find out what it was, even part time, for your own piece of mind. In my experience, part time = full time eventually when something is failing.

 

Nigel Thorley says in his book that the gearbox switch is a common source for lots of weird faults. Might want to check there if it happens again. Then again, I only know what I read unlike all the others on this forum who actually know what they're talking about!

 

With the electronics and computer systems on these car you cannot tell whether the issue is a water temp sensor or a transmission clutch.

At the end of the warranty period Jaguar should present all owners with an OBDII reader.

 

I recently had my local Jag shop (not a dealer, much better) replace a tube that carries fluid to the cooler (was leaking). The power was reduced when it was cold, but as the car heated up the acceleration improved from a stop (like at a traffic light).

When he replaced the tube he replaced the fluid and now the car operates normally at all times (power is consistent whether cold or hot). I am thinking that the trans fluid that leaked out may have been the issue.

You may need to check the fluid level. I know that has to be done at the tranny with the car on the lift. You may be just a little low on fluid...I'd check it out, cause the tranny's on these cars are very expensive to repair.

 

Have you tried draining it and putting a new filter and fluid in it? I change mine at 75,000 and couldn't believe how dirty the old stuff was.

 

Welcome to the forum. Have you visited the new member area yet?

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Your above response is to a four year old thread. The OP has probably either resolved the problem or sold the car by now.