2006 TDV8 3.6 'Unfixable' Transmission Problems

[Tdv8-td5- guy]

Hi All. Last ditch effort here. My tdv8 developed a transmission issue on NYE. It came up on AA as  P0929 selector lever lock solenoid fault  

2 different garages have tried to fix this, including replacing the transmission control module, and a new gear selector kit. Land rover helpline keep pointing back to the module. 

4 months later im exhausted- my last hope is to buy another gearbox for the module and try that, if not ill be forced to sell it for spares.

All wiring been thoroughly checked and rechecked. 

Does anyone have any experience with an issue like this? Id hate to lose the truck but I'm at a loss of what else to do! 

 

[garrycol]

Take it to a landrover specilaist and they should be able to sort it and if the places you took it to were "specialists" and could not fix it then take it somewhere else.

Have you had the codes read on a LR specific code reader rather than the AA reader - it pays to get the codes read on the correct reader.

[Tdv8-td5- guy]

Yeah I did take it to a specialist, the codes we are getting is P0929 open circuit and P0928 shorted round. 

[garrycol]

It is just a common ZF transmission fitted to most 2000s LRs and BMWs etc - go somewhere else then.  Its not rocket science.

[Tdv8-td5- guy]

Nah sorry mate, you're not understanding. The whole gearbox been replaced

[Happyoldgit]

13 hours ago, Tdv8-td5- guy said:

Nah sorry mate, you're not understanding. The whole gearbox been replaced

Just reviewing this thread as admin, sorry I can't answer your question specifically but I'm a bit confused after reading through what you've said.

Initially you stated..

 

Quote

My tdv8 developed a transmission issue on NYE. It came up on AA as  P0929 selector lever lock solenoid fault  

2 different garages have tried to fix this, including replacing the transmission control module, and a new gear selector kit. Land rover helpline keep pointing back to the module. 

4 months later im exhausted- my last hope is to buy another gearbox for the module and try that, if not ill be forced to sell it for spares.

...but your last post states that the whole gearbox has been replaced?

If you could clarify what your issue is and what has been attempted / replaced in order to rectify the issue it may avoid misunderstandings.

Naturally I realise it can be tricky if you have not been directly involved in the workshop and are having to rely on feedback from mechanics / technicians🙂 

 

[garrycol]

Yes it is a bit hard to follow, so yes TDV8-TD5 Guy I am not understanding as you did not say the gearbox had been replaced but I agree you were thinking about it.

[Tdv8-td5- guy]

Hey All, thanks for the comments back, ok i'll try and lay out what's happened so far. On Dec 31st, the truck developed a 'transmission' issue. We called the AA who gave us a readout of a P0929 and P0928 (open circuit / rounded circuit)

The truck went into a local garage, who then asked us to send it to a land rover specialist (someone with land rover software, access to land rover helpline, etc.) We know that other garage, they are sent land rovers from all over the local area because they are the local specialists. There is no question on their competency. 

The gearbox was bench tested, it was identified with the help of Land Rover, that the Transmission Control Module was at fault. 

A module was purchased, it was replaced. The truck did 30 miles, and the problem re-emerged. We also replaced the gear selector switch to rule out the selector solenoid.

Land Rover helpline continued to point to the transmission control module. The garage also called the 6 speed ZF manufacturer (they did tell me name but i forget), who were very surprised that not one, but 2 modules have failed. 

I sourced a third module, we have replaced it again, all the wiring has been checked and rechecked multiple times, the garages electrician has spent the better part of 2 weeks on and off the checks. 

I got the car back today, after 35 miles I felt a surge, and yet again a 'transmission issue' - the car goes into limp mode. It happens as I accelerated. 

I've spent 4 figures trying to fix this problem and cannot believe i'm no further forward.  I was hoping to see if anyone had a similar experience or could at least point us in the right direction, but both land rover and the gearbox people are also a little stumped. 

I'm very close to giving up at this point.

 

 

 

[garrycol]

You mentioned earlier that the gearbox has been replaced but does not seem to have happened in your chronology of events - so at what stage was the gearbox replaced. 3 modules replaced but nothing about the gearbox change.  Appreciate the modules seem to have failed when installed after a short time but were they then tested off the gearbox to see if they had failed?  It would seem to me that something in the gearbox or elsewhere is causing the modules to not perform - clearly there is something else going on.

[elbekko]

14 hours ago, Tdv8-td5- guy said:

Hey All, thanks for the comments back, ok i'll try and lay out what's happened so far. On Dec 31st, the truck developed a 'transmission' issue. We called the AA who gave us a readout of a P0929 and P0928 (open circuit / rounded circuit)

The truck went into a local garage, who then asked us to send it to a land rover specialist (someone with land rover software, access to land rover helpline, etc.) We know that other garage, they are sent land rovers from all over the local area because they are the local specialists. There is no question on their competency. 

The gearbox was bench tested, it was identified with the help of Land Rover, that the Transmission Control Module was at fault. 

A module was purchased, it was replaced. The truck did 30 miles, and the problem re-emerged. We also replaced the gear selector switch to rule out the selector solenoid.

Land Rover helpline continued to point to the transmission control module. The garage also called the 6 speed ZF manufacturer (they did tell me name but i forget), who were very surprised that not one, but 2 modules have failed. 

I sourced a third module, we have replaced it again, all the wiring has been checked and rechecked multiple times, the garages electrician has spent the better part of 2 weeks on and off the checks. 

I got the car back today, after 35 miles I felt a surge, and yet again a 'transmission issue' - the car goes into limp mode. It happens as I accelerated. 

I've spent 4 figures trying to fix this problem and cannot believe i'm no further forward.  I was hoping to see if anyone had a similar experience or could at least point us in the right direction, but both land rover and the gearbox people are also a little stumped. 

I'm very close to giving up at this point.

 

 

 

Sounds to me like something in the gearbox is causing the modules to burn out maybe?

[Snagger]

Three separate modules failing is exceptionally unlikely.  I’d imagine it is a sensor or wiring fault that is damaging the ECUs.  Checking wiring for continuity and shorts is often unreliable - continuity checks seldom reveal high resistance from corrosion or broken wire threads, but high resistance with some continuity could throw an ECU or sensor reading.  A short circuit in a wiring bundle could easily be hidden when testing with the harness in a different position than it sits in service.

But as the others say, an internal fault in the box, probably in the solenoid controls, could also be burning out the ECU by creating a continuous signal instead of a brief pulse.

What is the name of the specialist you used?  Some are more “special” than others.

[Tdv8-td5- guy]

Hey all

Thanks for all the comments! I checked with the garage, they only did a bench test, they kept the original box - they looked inside and it looked good so didnt feel the need to swap.

There is however a new, weird update. I read on another forum about handbrake issues. So what happens now is:

If i put handbrake on, turn on truck, take of handbrake and press it again, i get a different fault (just transmission issues but not limited gears only). That fault I think clears (dissappears from dash) And its not in limp mode. I can drive quite nicely, until I hard accelerate (over 2.5k revs) then the fault comes back with limited gears.

I pull over, turn off and on, fault clears.

I have another garage lined up to do a full box replacement but i really feel like its not mechanical.

I checked the ebay ad, and noticed it had a remap. Im wondering if that has any play here.

I really appreciate everyones input, im at the edge of my car knowledge at this point and burnt nearly £2k trying to fix this problem. Painful.

Edited April 15, 2022 by Tdv8-td5- guy

[elbekko]

10 hours ago, Tdv8-td5- guy said:

I checked the ebay ad, and noticed it had a remap. Im wondering if that has any play here.

Maybe. Is it a proper remap or a power box? Could be the gearbox is receiving data that's out of range of what it's expecting.