XK8 Transmission Trouble

This is going to be a long post because I experienced several problems with my transmission over the past several years.  It is long because each problem I fixed was good for a while then another issue would pop up.  So I will do my best to explain each issue to the end.

Keep in mind that the shifter in the car operates a cable that attaches to the shifter linkage on the left hand side of the transmission.  That linkage goes from the left side of the transmission to the right internal to the transmission and attaches to the shifter selector switch on the outside of the transmission on the right side.  The selector switch attaches to the transmission control module and the transmission control module controls the transmission shifting based on the information it gets from the engine control module.  Also, I want to mention that the lights on the shifter is only a device to tell you what you selected.  It does not come direct from the transmission.  It is from the CAN system


Issue 1:  Every now and then when putting the shifter into D it would not up shift and would only stay in first gear.  When this took place I would put the shifter into the manual mode #4 and it would shift properly every time without issue.  What I found was that the shifter was out of adjustment.  Now this could take place if a linkage bolt is loose on the transmission or the shifter cable has stretched from age.  However, I did not know that at first so I began checking electrical connections thinking the problem was electrical.

A reminder before you disconnect any electrical device - disconnect the battery cable.

I removed the control plug from the transmission and checked the pins and sprayed both ends with CRC contact cleaner and reinstalled it.  Once installed, I checked that it was securely locked in place with the locking ring.

Plug location on the transmission.  Left side of transmission.

Went to the other side of the transmission to make sure the selector switch was securely fastened.

This is the plug that comes from the selector switch and goes to the transmission control module harness and was cleaned with contact cleaner.

I then went to the transmission control module and checked the connections and cleaned them.  The plug is a little tricky to get off so whatever you do, do not force it off.

After I cleaned all the connectors and verified they were seated properly, I reconnected the battery and took it out for a run.  No Joy!  Same problem.  Got it home and began reading a little more and on a hunch I elected to check the shifter cable adjustment.

I first put the shifter in N and put the car on the lift.

Looking at the selector linkage I took a square and scribed a line on the linkage. 

I then removed the shifter cable attachment.

With the cable detached I moved the shifter all the way back and brought it up 3 clicks and noticed it was a little out of adjustment.  I brought the car back down and removed the shifter cover and began to make my adjustment. 

Now my procedure is a little different than that of Jaguars.  I did it this way to see what I had going on first.  I did not want to be pulling the console apart unless I had to.  This link is to Jaguars procedure on adjusting the cable.

Link   http://jagrepair.com/images/TSB/307-01-1.pdf

After I adjusted the cable I did not have an issue with the transmission up shifting.  All was good for several thousand miles.


Issue 2:  I began to experience a pulsing feeling at speeds of 55, 65 & 70.  I could push the car quickly from 55 to 75 with no issues but when cruising it would pulse but not all the time.  Then a few times it would be slow or harsh going into gear.

So back in the shop and a little more research.  Thought I would start by checking the transmission valve body.

At this point I was testing my volt meter for accuracy so I could begin testing the control valves and speed sensors in the transmission from the transmission control module plug.

First I disconnected the battery.

I went to the cars electrical diagram under transmission and traced the pin numbers for the control devices in the transmission.  Use this link and go to Lesson 4 page 68  http://www.jagrepair.com/images/Training%20Guides/201_SG.pdf  Well you should look over lesson 4 anyway.  This will give you the readings for the shift solenoids and speed sensors.  With my car they tested good so I elected to send my transmission control module out to have it tested.

I sent it to ASI and they found a problem and repaired it.  With the valve body testing good and the transmission control module repaired I felt I had the problem fixed.  I installed the transmission control module and drove it.  However, that was not the fix. It still had an issue and it began to get worse. 


Issue 3:  I elected to pull the transmission pan and see what is going on.

Removed the drain plug and let it drain into a container.

I removed the bolts on the pan.  When I did, I left one bolt in on each side so I could hold the pan and only have two bolts to take out.  I did not want to bend the flange that seals it to the transmission.

2 bolts and the filter comes out.

This is the transmission valve body still mounted.  Now to remove it you do not need to take all the bolts you see out.  I will attach a link that will show you the bolts that need to come out.  You do however, need to know where the long and shorts came from.   http://jagrepair.com/images/TSB/ZF5hp24%20valve%20body%20TSB.pdf 

This is the pan removed.  If you look hard you will see shavings in the pan.  I was not alarmed but I should have been.  I took the pan over to a transmission shop and they sounded a little concerned but felt it was ok.  They said it was not unusual to see a few shavings so I elected to continue.

The old valve body.

I did all I could to see if I could find anything that would give me concern but did not find a thing.

The new valve body and filter installed.

Cleaned the pan and checked the lip to be sure it was flat and ready to install.  When I cleaned the pan I sprayed it with brake cleaner to remove any residue left from the rag I used to clean it.

With the pan on and plug installed I was ready to fill the transmission.  I purchased this pump to get the fluid in the transmission.  It worked well.  The fluid I used was Lifeguard 5.  http://jagrepair.com/images/AutoRepairPhotos/ZF%20Transmission%20Oil%20Reference%20Guide%20PC%20102307.pdf

The fill plug is located on the right side rear of the transmission.  It looks like it might be hard to get to but it is not.  Reaching it is a little awkward but can be done. The hard part is when the exhaust is heated when filling but I did not see it to be a problem.

This is the plug removed.  The swivel was not necessary but made it a little easier.

I added the fluid to the pump and just squeezed the trigger and in it went.  I was able to put about two quarts each time.

I filled the transmission up until it started to flow out and I installed the plug temporally.  I started the car and with my foot on the brake I moved the shifter in all gear locations then back to park.  I did this twice.  Then with my pump full of fluid I opened the fill plug.  No fluid!  I checked the temperature as required to 30c 50c and would remove the fill hose to see when I have the drip.  When that took place I installed the plug.  I then let the car cool down.  I then started the car with my foot on the brake and I moved the shifter in all positions then back to park.  When the transmission reached the 30c I removed the fill plug and added a little more fluid until I had the drip.  I installed the plug and I was ready to drive. 


Issue 4:  Drove the car and it shifted and ran great for about 2,00 miles and then I began to have serious problems with shifting and noise.  I was so done with all of this.  I had ordered the valve body from Eriksson Industries. Link  http://www.erikssonindustries.com  and called them on the phone for assistance.  After much conversation I ordered a replacement transmission and installed it and as of today all is good.

Looking back I should have replaced the transmission when I dropped the pan and saw the shavings in the pan.  When I questioned the presence of the shavings, that should have been a red flag.


Issue 5: I did not take photos of the transmission replacement but the only difficulty in replacing it was getting the old transmission down and the new one installed.  I had a friend help me and he had the transmission lift.

In short we removed both cats, the transmission cooling lines and the bracket for the electrical connectors mounted on the top of the transmission.  We then disconnected all the electrical connectors and the driveshaft.  I put the transmission lift in place and unbolted the torque converter, the transmission mount and unbolted the bell housing and guided the transmission out and down paying attention not to bend or destroy anything.  We then flushed the transmission coolant hoses/tank. 

When I purchased the transmission I was told that it was full and had enough fluid with the system flushed.  After it was installed I drove it for a few miles and elected to check the fluid level again and when I did it was about a half quart low.  I filled it to the drip and was done.

I hope this helps.





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