Got in the car and started driving home tonight when I realized that the message "Gearbox Fault" started flashing. On the highway I also realized the tranny would not shift from either the 1st or 2nd gear. I tried to shift it manually but no go. I drove it slow through back roads and on a stop sign I simply turned off the car and re-started it. The problem went away.

When I got home I hooked my AutoEnginuity software and pull two codes from the Transmission Control Module:
- P0783 - 3-4 Shift Maufunction
- P0730 - Incorrect gear ratio.

Another possibly related symptom that I have with the car is that the 1 - 2 gear shift sometimes is pretty hard!

Now, some more details:
I did a tranny service about 200 miles ago. I replaced the pan and followed the published instructions to the tee (in terms of filling the tranny at the right temperature and waiting until it drips. I used ZF-Lifeguard fluid BUT it only took 3 quarts.

So, could the tranny fluid be low and cause this issue? If not, what else should I worry about? I will put it on the lift this weekend, check the fluid and respond back. In the mean time, any thoughts will be appreciated.

 

Sounds like you need a TCM software reload,(aka "reflash") and reset to cater for slight wear in the gearbox. This should correct your problems. However when you did the fluid, did you check the enry point for the connection to the TCM ? This can start to leak fluid which gets onto he pins and gives false info to the TCM, which is in the gearbox

 

Yes, I did replace the sealing sleeve when I did the transmission service even though there was no visible problems with it as a matter of principle since the pan was being replaced.

I checked the fluid level again this morning and it was perfect. So, no problem there. I did attempt to reset the TCM adaptations but even though I have the Jaguar enhanced module for the AutoEnginuity software, it returned an error saying that the command is not supported on my vehicle.

I did clear all the codes but the P0730 evidently does not get cleared. I do not know what the deelio is there.

I'll drive it next week and see what happens until I figure out a way to reset the TCM.

 

Maybe the fault is real and a repair needed.

 

Well I have never heard of a pan drop only take 3Q of fluid. Everyone else is at 6-7L depending on how long you let it drain. That is way out of line somewhere?
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Indeed! I just talked to a mechanic today and really feel embarrassed. The car was NOT running when I filled the tranny cavity while it is running and the temperature is between 30 - 40c. Totally my mistake. So, back in the lift tomorrow to refill the cavity with the missing quantity of fluid. I probably put about 250 miles with low fluid level and only acted once so I am hoping that no permanent damage was done.

 

Hey glad you found it! That should totally fix your problems. Don't think you drove it far enough with low fluid to hurt anything.

Good catch!
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I jacked it up today and the tranny took an additional 2.5 liters of fluid. I put about 400 miles with the fluid being low. I'll be putting some miles on it tomorrow to see how she does.

 

Any update if this worked?

 

Mine is acting the same way. But mine was acting like that before I replaced the fluid and sleeve. It still does it every once in a while. I went to the dealer to have it reflashed and they told me not to because it had the shift fault. They said that the engineers told them its not recommended because it the transmission may not be able to relearn adaptions because it could be too far out of adjustment and may cause the transmission not to work at all after the reflash. Has anyone heard of this? How true is this? Is the dealer just trying to get rid of me and hope I'll come back after the transmission fails?

 

Yep. 14,000 miles later without a single tranny incident.