So I recently purchased my 2001 XJ8. It was being somewhat wonky (as expected) the day after I purchased it. It was throwing gearbox fault and putting me into limp mode, but about 50% of the time there would be no gearbox fault at all and it drove completely normally. It also was giving me a low coolant indicator so I did a coolant flush and refill and that warning persisted even with the coolant levels remaining appropriate and no indication of overheating.

Regardless I turned it on this morning and it gave me a gearbox fault. I put it in reverse and it jerked pretty heavily even with my foot on the brake. I decided to take my other vehicle to work and let it sit. After work I did it again to see if it had resolved itself once again and it jerked again. I then turned it off and on and the gearbox fault was gone so I put it in reverse and now it does not reverse whatsoever even when revved. The forward gears still work as well.

Does anyone have any idea what could be happening now? And do you have any suggestions on what to do next?

Thanks a lot guys.

 

First suggestion, don’t park facing a wall.
Seriously, these trannys fail quit frequently. Lots of threads. No expert but the first thing to do is check fluid level. Low fluid could cause. Not easy to do without a lift because no dipstick and car must be level.

 

Wonky is right! Not so much for the 2003 XJ8s it seems, though the posts concerning transmission issues might be slanted.
It is a bit odd that Jaguar intended these trannys to be completely maintenance free, yet expected to last the life of the car.
I have had the Duchess in for a couple of checks over her time with me, and the technicians report no issues. She shifts just
like new, but there is always the specter of a $4000 repair bill that might come unexpectedly knocking.

 

Thanks for your reply man. So I researched more and I decided to troubleshoot a bit with the gearbox. I slowly shifted it until it pulled into reverse. When I did it shifted way higher up the track than it should of (quarter inch above the notch for reverse). And guess what it worked with no problem whatsoever. I noticed neutral shifts so high up the track that it could appear to be the reverse gear. I think my cable in the gear box is loose and that the error occurs randomly because the car thinks I’m in multiple gears at the same time. I definitely think this is a gearbox issue and will be taking it apart this weekend.

Drove it today slowly shifting it into gear and it drove like a champ.

Weird…

 

Here’s a source showing similar issues as to what I’m dealing with:

 

Almost guaranteed its either a broken valve body, bad power valves, or bad "A" drum or any combination of those.
A site member just replaced his broken valve body this weekend.
Here's a list of power valve kits on Ebay... https://www.ebay.com/sch/i.html?_fro...e+kit&_sacat=0
That kit is technically mandatory to do or you face the consequences later. It doesn't fix the already broke issue, it helps prevent the next one.
Watch this from Gary Ferraro...

 

Here's another one to review...

 

It may be wise to check the shifter mechanisms first, just a thought.

 

Hi guys
Just my 2 cents - I had similar issues with my 2001 jaguar Vanden Plas 4.0L. HP24. Car Sat for a few years before I got in 2019.
With the help of Highhorse and CK.
we got the car running good.
I have a post on here asking for help with Jack stands placement. You'll see how those two helped me out..
After the engine was done i replaced the VB pressure valve.

Before i replaced the pressure valve and fluid, filter. Reverse was fine maybe a little delay,drive definitely had a 3,4 second delay but it drove fine shifted fine.
It was after that I found the information about the upper valve body issue, you know that they crack from over pressuring due to warn pressure valve.
when I went to do my 2nd fluid and fillet change i thought I better drop the VB and check , sure enough it was cracked a fine crack but cracked. At the time I want able to find just that part. I Contacted Gary Ferraro he tried to locate one no luck he recommended Eriksson's again no luck. I put it back in the car just to keep everything together and clean i left it alone for almost a year . Now almost 2 months ago I decided to have a local shop do the job of removing it and welding it.
highly recommended shop ,spoke with the owner went though every little thing , was told his son in law who works for him is an excellent welder. Great I had the car towed to him , left him 2 1/2 gallons of lifeguard fluid, new ZF Filter and On ring, gasket, torque specs... a week went by and one of the guys call me and said the car was ready.
Oh Boy.... The drive home is less than 7 miles, it felt better than I remembered it did until about an 1/8 mile from home and Boom! It down shifted and wouldn't accelerate felt like it was in a high gear.... Anyways i was back to the Hell with this POS I left it alone. Call the shop owner was away...
days later I had a buddy help me get back on jack stands had him drain and drop the pan 1 st noticed bright red fluid new filter from Napa no gasket just sealant.
Then the Valve body.
This is what i found...


Yeah they welded it alright !
JB Weld.


Anyways that part is available now for my car what is important is that Casting Number.
Now have the New upper body new filter, Oring and correct fluid .
Drove it yesterday for about 40 mins . No delay in shifting from park ,reverse to drive, on the road shifting was smooth on a flat straight road I was doing 60 at just over 1500 rpm...
So far So good...

Hope this helps someone...

I thought putting the VB in the dishwasher is what caused this...
But Highhorse said ithat was fine go for it... 😂

I will say Highhorse is a Good Man and Very knowledgeable him and CK talked me into taking out a 2nd mortgage to repair this car.
Carnival kid Sorry he passed he's missed .

 

Wow! MrJay, that is distressing about the local shop. He did not consult with you at all?
We are certainly happy you found the part you needed and that it is now sorted.
It is true that these sophisticated cars require sophisticated effort.

 

No Consulting. I thought I was clear remove the VB Weld that one section if possible, If not I'll pay for the time you spend on it and take the car home. That was pretty much my instructions. Plus I supplied fuilds, filter gasket, O ring.

If you met the owner you would have no doubt he's a good man. In the end he turned out to be a good man , He Came to my home I showed him what was done he apologized up and down his wife was in shock and refunded me on the spot. He also offered to do it himself if I got the part no charge.
He explained to his son in law what was needed (the so called welder)
and left the state for a family emergency. In the end I got everything back plus 12 qts of lifeguard. The story is much longer this is just the short Version. Lol..
The rest was me dropping the F bomb! And threats of retaliation.
I've never had a shop do any repairs to my vehicles I always found a way to repair them myself. With help from people more knowledge and help from this site and the good guys on here, I'm now happy with the car again...
Next - Steering Column, one tilt motor gear is stripped. Can't get the cluster out to replace burnt out bulbs. Again that isn't something I think i can do without someone to physically get under there and remove it. ( neck injury )
This car has caused alot of grief between me and my GF. Bodily harm, and money, But truth be told I do enjoy messing with the car and seeing it come back to life...
Plus though this site you get to meet some good people willing to help and share their knowledge.
Aways I know long-winded story about nothing. But I thought I share my experience.
Thanks guys.