It looks like my xk8 has a dying tranny again. ZF and Jag will not see my business
#61
11-11-2016 | 05:09 PM
Thread Starter
|
Senior Member
Joined: May 2013
Posts: 970
Likes: 119
From: PA
The transmission has a valve body ( that is your shifting) that takes command from the transmission control module (TCM) that takes commands from the shifter selector and all is directed by the engine control module. You put it in gear “D” the TCM says ok you want to go forward. The TCM talks to the valve body and the transmission is ready to go. When you accelerate the ECM and TCM are talking and making the decision on when to shift based on the engine conditions and RPM and a few other things. Along with the valve body that is telling the transmission what gear to be in the 2 speed sensors in the transmission are reading the input and output speeds of the drives in the transmission.
I am assuming that the engine is running properly so let’s move on to the transmission.
Because you are having shifting issues I would focus on the shifter selector switch, TCM and valve body. Since you say the shifter is adjusted properly and the battery is good and the fluid level is correct we can move on to the TCM and the valve body. Now the TCM can be sent to ACI to have it tested and I have done this they can make repairs if necessary. As for the valvebody you can take pin readings at the plug at the TCM or at the transmission, I did it at the TCM. However, it will only tell you if the shifter solenoids and speed sensors are good it will not tell you if one of the valves in the valve body are sticking or stuck.
How many miles do you have on this rebuilt transmission?
I am assuming that the engine is running properly so let’s move on to the transmission.
Because you are having shifting issues I would focus on the shifter selector switch, TCM and valve body. Since you say the shifter is adjusted properly and the battery is good and the fluid level is correct we can move on to the TCM and the valve body. Now the TCM can be sent to ACI to have it tested and I have done this they can make repairs if necessary. As for the valvebody you can take pin readings at the plug at the TCM or at the transmission, I did it at the TCM. However, it will only tell you if the shifter solenoids and speed sensors are good it will not tell you if one of the valves in the valve body are sticking or stuck.
How many miles do you have on this rebuilt transmission?
#62
11-11-2016 | 07:20 PM
Thread Starter
|
Senior Member
Joined: May 2013
Posts: 970
Likes: 119
From: PA
Oh and here is another good one. So I realized I never checked the fuses so I pulled the number one for the TCM on the left hand box, just but swapped it for another and then pulled the #4 fuse from the box right in front of the TCU (says EMS. ECU TCM 5 amp). Again fine. Figured I'd run it without this fuse thinking it would probably kick a ton of codes. Well it didn't, it ran exactly the same and thru the same p1794. Any thoughts on this. I did check voltage before swapping fuses and while running it had a lovely 14.1 on the fuse block.
#63
11-11-2016 | 07:28 PM
See if this helps. Go to lesson 4 then go to page 64. It will give you the reading for checking your speed sensors and solenoids.
Link http://www.jagrepair.com/images/Trai...des/201_SG.pdf
Also for the pin locations use this link and go to Fig 5.1
Link http://www.jagrepair.com/images/Auto.../jagxk1997.pdf
Have you ever visited my web page?
Link http://www.jagrepair.com/images/Trai...des/201_SG.pdf
Also for the pin locations use this link and go to Fig 5.1
Link http://www.jagrepair.com/images/Auto.../jagxk1997.pdf
Have you ever visited my web page?
The following users liked this post:
BobRoy (11-12-2016)
#64
11-11-2016 | 09:09 PM
Thread Starter
|
Senior Member
Joined: May 2013
Posts: 970
Likes: 119
From: PA
See if this helps. Go to lesson 4 then go to page 64. It will give you the reading for checking your speed sensors and solenoids.
Link http://www.jagrepair.com/images/Trai...des/201_SG.pdf
Also for the pin locations use this link and go to Fig 5.1
Link http://www.jagrepair.com/images/Auto.../jagxk1997.pdf
Have you ever visited my web page?
Link http://www.jagrepair.com/images/Trai...des/201_SG.pdf
Also for the pin locations use this link and go to Fig 5.1
Link http://www.jagrepair.com/images/Auto.../jagxk1997.pdf
Have you ever visited my web page?
The world has become too much of parts replacers unfortunately. To that end I can't even find anyone willing to replace the valve body only a tranny which as I already stated I will not do. I had a hard enough time justifying it when I did it the first time at 95k.
#66
08-18-2020 | 09:21 PM
Junior Member
Joined: Sep 2014
Posts: 6
Likes: 1
From: Leland, NC
Well after having my tranny rebuilt by the ZF factory rebuilder 2.5 years and 20k it seems my tranny is on the way out. Getting 1798 and 1799 codes. It will hold speed a bit at times and hard downshifts when it is holding speed. Also, got in it today to and it wouldn't go. Stopping and turning it off usually resets it. for a while. Battery is good in fact this morning it had just gotten off a tender trickle charge cycle. Any thoughts?
This will be my last Jag so long as they continue to use ZF trannies. They are simply junk.
This will be my last Jag so long as they continue to use ZF trannies. They are simply junk.
Just a thought, Ive owned quite a few two seat performance sports cars and I aways have the most off the wall 2% statistical chance type stuff happen...
Lots of Luck,
C. Poling