Well, It seems that whenever I work on my 2003 XJ8 with 133000 miles, I create more problems than I fix....
Yesterday I replaced the secondary timing chain sensors, using the Zip tie method outlined here, changed the oil and filter, rotated the wheels/tires. All with no apparent glitches. Prior to starting the car and changing the oil, I removed the fuse for the fuel pump and cranked the engine over for about 20 seconds to provide oil to the new tensioners. Upon starting, there was no problems observed, engine started well and ran smooth. Shut the engine down and checked for any leaks, there were none.
When I restarted to take the car for a road test, there was very sluggish response to the throttle. It was in limp mode and had the "gearcase fault" light on.
Now prior to doing this work, the transmission had never exhibited any sort of problem.
Can someone tell me what I may have done wrong to cause this new problem?

 

Without interrogating the ECM and TCM for DTCs you are really just guessing.
Get the codes read and see what the modules tell you what they are faulting.

bob gauff

 

Bob, thanks for the reply. I had the Auto Zone store scan the car for me yesterday. I had two codes; P0128 and P1111. I should mention that I replaced the thermostat and cooling sensor about three weeks ago thus accounting for the P0128 I think. The other code doesnt seem to be pertinant but I checked all the connections that I had removed during the Tensioner replacement. Could I have damaged a sensor and would it cause the transmission fault? Also, Battery is fully charged.

 

P1111 Readiness set so all the monitors are complete.
I guess you did not reset the ECM when the coolant thermostat was replaced??

There could be some DTCs in the TCM but you would need an enhanced diagnostic computer to read those.

A full scan of the modules and the CAN bus might help but you might need the dealer or someone with WDS,IDS,AutoLogic,AutoEnginutiy, etc.

bob gauff

 

Check all the plugs on the Throttle Body and the MAFS or any other plugs you pulled on or pushed around.

 

Well, It has a 1722 code and the fluid is black (very dirty). Based on what I have read on here, I'm surmising that it's the A drum coming apart. Working on a solution now, Considering relacing he A drum but leaning toward a rebuild as it has 134 K on it, and is so dirty.

 

Hi lowride
Here is a great write by XJRJeff and other forum members posts in the following thread on rebulding steps on the ZF5HP24 transmission including valve housing parts:

https://www.jaguarforums.com/forum/x...d-again-61537/


Here is the weblink to the ZF524hp transmission repair manual (see post#1):

https://www.jaguarforums.com/forum/x...hed-faq-54929/


Here is the weblink to DIY on replacing the A disk in this transmission:

https://www.jaguarforums.com/forum/x...y-27985/page3/

Here is the weblink to my own personal experience on having our ZF5hp24 transmission rebuilt (see post#5):

https://www.jaguarforums.com/forum/x...trouble-43202/

Jim Lombardi

 

Has the "gearbox failure" continued after a reboot or erase? A couple of times that error message, along with limp mode, came on when I was scanning. Just shutting down or rebooting fixed it.
Good Luck

 

The problem was the transmission. It has been repaired and is back up and running great. Thanks for all the input!!!