on my 2004 XJ8 the plug on the valve body in the tranny appears to be leaking transmission fluid right through a few of the pins causing all kinds of fault codes. Has anyone ever heard of this? Can the plug be fixed?

 

It's a common fault, and needs a new seal putting in. The seal is cheap the main cost is labour. What miles on the car ? It might be time to change the fluid and filter, and the seal can then be done at the same time. You are right about the pins and fault codes; they will all have to be cleaned up if the leak is a bad'un.

 

Great, it has 127K miles, I was hoping there was a seal. I did just have the fluid changed and I was afraid that it loosened something that was being sealed by the sludge. I have changed the fluid every year.
do you have to remove the valve body to replace the seal?

 

The sealing sleeve has o rings that eventually leak. It is locked on the inside of the tranny, so the plastic pan/filter has to be removed to do the job. The sealing sleeve is available from THE CTSC online.