When I put my car in drive, I can feel the transmission will sometime jerk very hard and the rear wheels will lock. It seems as though reverse gear is trying to engage while the car is in drive. Today, while I was sitting on level ground, I took my foot off of the brakes and it began to go in reverse and then switched back to drive. If I keep my foot on the brake pedal and the gear selector is in drive, I can feel the transmission jerk when it reverse tries to engage. I had the "Gearbox Fault" and "Restricted Performance" codes showing, but they were gone when I restarted the car. Is it time for a new transmission? Has anyone else had this issue?

 

How many kilometres/miles are showing on the instrument cluster?

Are there any DTCs stored, and is the MIL on?

Has the gearbox been serviced?

With the ignition in the OFF position for at least thirty minutes, what is the available voltage when checked with a voltmeter across the battery terminals?

 

Good morning,
The car has 141,128 miles showing. The MIL was on with the "Restricted Performance" error showing until I started the vehicle, then the light went off and the message disappeared. When I turned off the ignition and turned it back on, the light remained off with no error message showing - only the mileage.
I am unaware if the gearbox has been serviced. I have owned the vehicle for a very short time, but the previous owner (for over 15 years) said that this issue occurred with her a couple of times. The battery is new and was installed a week ago.
Thank you for your reply!

 

It could be as simple as the joint in the rod between the lever and the g'box
You know the one where the bolt falls off and ends up on your drive?
Maybe it is just loose but on the way to the common fault.

 

I am not familiar with the bolt to which you are referring. Would that cause the transmission to try to engage reverse gear while in drive?

 

Just because the battery has been recently replaced doesn't mean it's fully charged.

Check the voltage with a voltmeter before doing further diagnostic work. Guessing on a Jaguar can become very expensive very fast.

As has been suggested above, check the linkage to the gearbox as the two 8mm bolts can become loose, or fall out causing the gearbox to not shift correctly. Use the search function of the forum to find the threads discussing this issue.

 

Thank you! I will search the forum and check the bolts. That would be great if it is as simple as that.....

 

Hi, I found a great discussion that not only addressed the bolt issue but provided an excellent picture of the location of the mount. The bolts on my car are intact and tight. The battery voltage is 12.66 without the vehicle running, so it appears to be sufficiently charged. When I drove the car onto the ramps for access to inspect the bolts, it performed as it should. However, as I held the brakes and kept it in drive, I could feel the transmission jerk when the reverse gear tried to engage. I have googled and searched and I have not been able to find anyone who has posted about this specific type of issue. Maybe I am not using the correct search terms - I entered - 2004 Jaguar XJ8 reverse engages while car is in forward drive - so I would think that would provide some related results. I have seen a lot about cars being stuck in park or not engaging in forward and/or reverse, but I have seen nothing that fits the issue with this car. I would like to repair the car, but I would prefer to know what is causing the issue rather than simply chasing it with replacement parts.

 

It's usually one/both of those bolts but maybe the other end of the cable is loose (or stretched)?