Several month back, the gearbox fault alarm cam on in my 2003 XK8 (72,000 miles). It went into limp mode in one gear and got home okay. Well, due to the talk about the gearbox squack(spelling), I have planned to change the fluid out anyway. I did so and went with the Ford Mercon fluid for ZF gearboxes as it was cheaper than the ZF fluid. Well the car ran fine but the occasional squack would happen still. Today, I bit the bullet and put in the ZF Lifeguard fluid and took it for a drive. The car drove fine, shifted great and all was terrific until about two miles from home when I heard that old familiar noise again and suddenly the "gearbox fault" message came up and I went into limp mode.
The method I used both times was to fill the box until it started to run out. Then I started the car, put it in each gear for a bit and then back to park where I let it warm up until I got a reading of 40 degrees C on the bottom of the transmission pan and had a small overflow stream coming out of the fill hole. I then put the plug back in and cleaned up.
Any ideas? Can't figure why with the Ford fluid, I had the noise but no limp mode issues.
Thanks in advance for any and all ideas before I shoot this thing. It has been a disappointing car during my first year of ownership. My 1969 E-Type was less problematic.

 

While the fluid was warming up, you kept filling the whole time, right? You should put around 6 quarts before it starts draining out.

Generally speaking, you should take advantage of these "gearbox fault" messages to read the codes through the diagnostics port. They can more than likely point you in the right direction.

Next, as a shot in the dark, check that the ABS reluctor ring is solid with the axle shaft on the driver/rear wheel hub, right "under" the ABS sensor. If not, the ECU is not getting a consistent read on the vehicle speed and the transmission "gives up". That ring has been known to get loose and create all kinds of problems.

Last, if none of this leads anywhere, you might want to drop the pan/filter and check the 2 big magnets for any type of mechanical damage (metal shavings). These transmissions are generally very mechanically reliable, so this is unlikely.

Best of luck, keep us posted.

 

Thanks for the reply.
I did notice that the time I put the Ford Mercon fluid in, it took 6 quarts. This time it took only 5 with the Lifeguard.
I filled it until it was draining out and then started it, went through the gears and let it warm up. I never had to add more as it never stopped draining out as it warmed. Should I have had to add another quart? I wondered about that


FYI, the pan was replaced and nothing was noted on the magnets. Not all fuzzy like I have seen in other pans.


I never thought to look for specific codes when the message came up. Are they stored or do they reset when you restart?
Thanks

 

a few guys here have had to change the fluid 2x till it was right.

 

^^ Yep, my wife's 2006 XK8 continued to "squawk" in hot summer weather after we did the pan drop, sleeve change, and ATF refresh using Lifeguard 6 back in July 2013....

When we did the drain-and-fill using Mercon SP in April 2016, the ZF squawk disappeared for good. We're planning to do one more Mercon SP drain-and-fill this coming October to ensure that at least 85% of the ATF in the system is Mercon SP....

 

I thought that I posted this already but cant find it.
Well, it gets stranger. Hooked my OBD diagnostic tool and found two codes.
A P1111 which I think is normal and a P0735 code which says something about incorrect 5th gear ratio.
Then, when I went to button it up, the drivers window had lost its memory and I had to go through the old up down routine to get it to stop at the correct height.


Any ideas before this car drives me up a wall???

 

At this point, checking the reluctor ring is your best bet. Take the driver rear wheel off, remove the ABS sensor (10 mm screw), and gently poke a screwdriver in the opening, trying to move the "teeth" of the ring around. If it is anything other than solid with the axle, that is the problem.

 

Interesting. I will give it a look this evening. Not sure how the window losing it's memory relates to all of this. I was wondering about battery issues,.
THanks. More as I learn it.

 

The window is a classic weak battery symptom, try charging it up before you pull too much apart.

 

THanks Norri. While I wholeheartedly agree, I was wondering if a weak battery could cause transmission woes also. All that being said, the car starts up lie the battery is fine. I will give it a try though. Thanks again for responding

 

Well, I "reluctantly" pulled the ABS sensor to look at the "reluctor" ring and the teeth on it do not move unless everything else, hub, disc etc moves. Not sure how one could move without the other but obviously it has happened. Did notice while in there that my top rear shock mounts are trashed and crumbly like my fronts used to be. Need to figure out how to access the top mount from inside but that is for another day. Any more ideas from you or anyone else are appreciated. Thanks again

 

What DTC(s) is/are in the TCM?????????????????

You read the ECM but the TCM will have more definitive code(s).

Let the guessing begin.

bob

 

Well Bob
I guess I need a special piece of equipment to read the TCM?
Looks like you were smart enough to have sold most of your Jags! I did too back when I worked as a Jag mechanic in the 80s. I figured since it was a Ford product, it would be more reliable like my 2003 T-bird.
On an interesting note, I took the car on about a 30 mile round trip this evening and it shifted fine and no issues whatsoever.. Go figure

 

This car is starting to remind me of my ex-wife. Easy to look at and miserable to live with!.
I have changed the transmission fluid to Mercon SP and continued to have problems. I did a swap out to Lifeguard 6 and have still noticed the squawk usually when I am at cruising speed and it downshift s to pass. Well, today, I took the car out for a 200 mile trip. When I was about 2 miles from my destination, I got the old "Gearbox Fault" alarm and limp mode activated. I just drove it like that as it was only 2 more miles. On the return trip, I would hear the occasional squawk at cruising speed when it downshifted but no other issues until I go back in town and stopped for a bite. When I restarted the car, I got a Check Engine Light and a Restricted Performance message. After a few hundred feet, the "Restricted Performance" message went away but the check engine light stayed on. The car ran on without any performance issues. When I got close to the house, I stopped and accelerated a few times and got the squawk plus it went into "Gearbox Fault again.
The last time I got "Gearbox Fault, I got a code P0735. I also tried at that time a $2000 analyzer to see if I could get other codes from the TCM but all it had was P0735. Disappointing to say the least. Well, I got home today and expected my P0735 and something else that caused the check engine light. When I hooked up my reader, it said 2 DTC codes. One was a P1000 and the other read N/A. The N/A could be cleared but not the P1000.
Any ideas? Does the tranny need a certain number of miles after a fluid and filter changed to clear up issues? I have had this car for 2 years and have put just under 3,000 miles on it. Primarily, it is saved for a nice day but also not driven because I don't want to constantly deal with this crap. Total mileage is 72,450. I had the battery tested at a local auto supply and it tested good.
Help! Ready to dump it if it doesn't start to behave better.

 

There are ONE of 2 codes that will ALWAYS remain logged in the ECM.
P1000 readiness tests incomplete.
P1111 readiness tests completed.

YOU CANNOT clear P1000.
It will clear itself when the readiness tests are completed and be replaced with P1111.

bob

 

I figured something like that was the case for the P1000 and the P1111 codes. Anyone got any ideas about the continued tranny issues or the fact that I got a Check Engine light and the code read N/A but cleared?
Thanks for any and all advice.

 

Sounds like a scan tool that isn't working right.

 

Tried a second tool with the same result. Forgot to mention that. Thanks

 

Also faulty, then.

 

Not positive about this, but it probably means there are stored error codes that are Jaguar-specific, i.e. not part of the standard OBDII. This means a generic tool is not able to pick these codes up.

For the larger question about what is going on with your transmission, at this point you need to somehow get access to a tool that can read those proprietary codes. There are several options, ranging from a visit to a dealer-type shop to getting your own scanner or even a copy of the factory tool. Once you have the codes (basically the transmission doing its own diagnostic and telling you about it), then you can post them here, or do a more specific search.

Best of luck, keep us posted.