4qts is not enough to refill if the pan has been off , that's for certain.

 

^^ I concur. Was the last ATF drain done only by removing the drain plug, or was the pan also dropped? If you dropped the pan, you probably needed to add between 6 and 7 quarts of ATF. If you only opened the drain plug, then 4 to 5 quarts will usually bring the level back to ideal....

I would use fresh Mercon SP with no additives. They sometimes do more harm than good....

 

I would say have the shop drain/refill with Mercon SP one more time, and double check against this procedure: jaguar-6hp26-6hp28-transmission-fluid-level-procedures. I would most definitely stay away from any additive not backed by ZF.

If you have a chance, have the codes read when all these errors are displayed. Get them all before restarting, etc. There are handheld Jaguar-aware code readers for not that much money.

You might have to put some attention towards the valve body next. People talk about the bridge seal and the additional rubber tubes (cheap parts, the valve body has to be removed, but the trans stay on the car). You can start there if the shop labor is not killing you. Next steps would be a set of new solenoids ($400?), or a rebuilt valve body altogether ($1,000+).

Any luck checking the reluctor rings?

 

Just a drain by the plug. 4 qts added.

 

Reluctor rings checked out fine.

Shop is VERY familiar with the refill procedure since I print it out for them each time they've done it and talk about it.

Will get current codes read and posted here.

Will schedule additional drain with valve body inspection.

Please keep the suggestions or thoughts coming.

 

If you read around the forum, there is some information about the early 6HP26 that have some problem with the torque converter seal, something that was later corrected. Not sure of the symptoms, but this probably something for later as it requires the trans to come off the car for replacement. Also, check there is no fluid behind the rubber/plastic plug at the bottom of the bell housing.

Next time the car is on the lift, have the shop check the electrical connector by the output shaft. Check if there is any leak around it, or, once the plug is off, inside the plug itself. This is a round plug with a rotating collar. If it has been messed with before, check none of the pins are pushed in too far and have bad contact. Take pictures and zoom in to double check. Use an abundant amount of contact cleaner and secure it back.

Folks have also mentioned there is a cable from the shifter that attaches to the side of the trans. There is supposedly very small hardware that hold everything in place, and can apparently come loose. Have them check that out too while on the lift.

All I can think of for now...

 

What's planned:

Decided to go with replacing the bridge seal and the additional rubber tubes. Thought this was a great reference page and I bought the parts there:
Transmission Fault ZF BMW Jaguar Range Rover Land rover

Will also have them inspect the electrical connector by the output shaft and if there is fluid behind the rubber/plastic plug at the bottom of the bell housing. New pan gasket and refill with Mercon SP. Hopefully that will fix it. I'll let you all know how I made out once the work is done.

 

Years back I was a transmission shop owner for several years. I don't like the black fluid on the rechange of fluid. Just not a good sign. However, if the tranny is not slipping you might get lucky.

The reason I looked at this thread is I also have a 2003 xk8. My transmission had something going on with one of the previous owners per talking to the dealer. Apparently they added an additive that took care of the problem. I'm very close to the 70k mark and would love to do a service on it. However, I am just going to leave it alone for now. Transmissions (ZFs) are very temperamental and I just don't want to add to any potential problems by doing a service.

Good luck and hopefully you can get this resolved.

Cheers!

Andrew

 

Update:
Finally got the car into my mechanic where the bridge seal and 4 tube seals were replaced. Fluid removed was clean, filter clean, electrical plug in good condition, bridge seal seemed OK and the 4 tube seals were bent and pushed into the valve body. Seal and tubes were replaced as referenced in ZF instructions I found online and fluid topped off with proper procedure. I picked up the car yesterday and it still had a hard shift only into 4th gear. It didn't fault the gearbox as before. I drove it home which is 15 minutes away. Today, I drove it to work and the same symptoms were present. Hard shift into 4th, but no faults. After work, I drove it to his shop to get some trans fluid I left behind and took it for a longer ride. After 30 minutes of driving, I was going up a hill and going into 4th the gearbox faulted. Pulled over and restarted the car to clear the fault, but next shift it faulted again. This happened 3 more times before I got home. Right now, I have an orange engine light which wasn't there before the faults started again. I will get the codes read tomorrow. Not sure where to go next, but I'm thinking a valve body rebuild. Any other thoughts?

Steve

 

To remain in the cheap validations for now, have you taken a HARD look at all your wheel bearings? Wheel speed is a major input into the gear selection. If the ABS somehow cannot read the wheel speed, the trans goes a bit crazy. Bad bearings cause the ABS reluctor ring to be off alignment. There was a long post about this recently. I believe the rear bearing matter most for this. There would likely be ABS codes for this, too.

Getting your own code reader would probably help a lot, so you could get all the faults as they occur. Folks seem to get JLR Foxwell or iCarSoft handheld units.

Have you checked the wire to the trans, and followed it around? If there is damage, it could break the CAN bus connection and trigger this "watchdog" error.

Is there a rough transition from forward to reverse? And then rough again reverse to forward? If so, check the output flange. There was a redesign at some point, and an S-type TSB I believe. Not sure a bad flange is enough to throw codes, though.

 

No problem with this transition or any other except going into 4th.

 

 

Besides the rings, check the bearings themselves. Bad bearings make a wheel rock and twist funny, probably somewhat randomly. You have to lift each corner and grab the wheel horizontally and then vertically and check for play. Mechanics can probably do that in minutes, mostly to put that theory to rest.

Having your own reader would let you capture codes as soon as you have these hard errors. I believe if you stop the engine and restart, some of those temporary codes go away. I figured you would want all the codes you can get to help you out. Some of those JLR readers are a bit over $100, not terribly expensive, and supposedly cover most if not all modules. Your call of course, but I am hopeful the ultimate answer will come from those codes.

Best of luck, keep us posted.

 

The temperature is available over CAN, but it is a proprietary code, so you need a JLR code reader (technically, the code has been identified, but nobody has put it all together into a series of steps for an ELM327 that I know of). You can definitely use an infrared thermometer. The procedure is to fill it up till it drips, let the temperature rise, and then close the fill plug as soon as it reaches the min temp (but not later than when it reaches the max temp). As there is a range of acceptable temps, closing the fill plug near the min temp as measured on the pan is likely acceptable.

 

I stopped in at my mechanic and had the codes read. There was only 1:

"P0783, 3-4/4-3 gear load fault, possible cause: ECM torque signal fault, transmission mechanical failure."
If you look back in this thread, it's the second time it's appeared by itself.
Are there any thoughts on this code? Does it relate to a certain part in the tranny?

Unless someone has a better idea, I'm planning on having the TCM and adaptions cleared as well as the firmware updated on the transmission. Seems like some other folks had success with doing this for harsh shifting. The only downside is my local dealer won't do it and the other closest dealer is booked until August.

 

This is an excellent read:

6HP26 diagnostics

 

The codes are better documented here: X103_P_DTC_OBDII

There is this recurring "ECM Torque signal fault", that seem to point to the torque converter. Double check the "monitoring Conditions" column for clues. Can you confirm the converter locks under the conditions listed?

 

Here's the instructions to check the converter:

"Drive the vehicle at 113 km/h (70 mph), then reduce the throttle angle until the torque convertor locks Ensure that the torque convertor remains locked for at least 1 minute"

Can anyone give me a clearer understanding of what I have to do and what to look or feel for?

 

Can anyone help me understand this?

"Drive the vehicle at 113 km/h (70 mph), then reduce the throttle angle until the torque convertor locks Ensure that the torque convertor remains locked for at least 1 minute"

So, I get the car up to 70mph. "Reduce throttle angle"? Does that mean I back off the gas or maintain speed? How can I tell the converter is locked? RPM? Feel?

 

FWIW, on my car (which I am not saying is perfect), there is a marked difference when I hit precisely 70Mph. The transmission "sloshing" noise are gone and all I hear are engine noises. Pressing the throttle just makes more engine noises. Below 70Mph, there are some transmission noises. It is a pretty obvious difference if you pay attention. That locking is when the engine flywheel and the converter are "solid" as for a manual transmission. From reading the text of the test, it seem to check that if you drive above 70mph at light throttle for at least a minute, the converter should stay locked, and if it does not, you would get codes or a limp home mode.