2grumpy

Hi Simon_CSK & Western & thanks for the reassuring words. In my case I don't think I had the option to reprogram the brain, as the fault codes generated by both code readers indicated a total failure to communicate with the TCM, with subsequently no option or ability to reprogram it. even with the dedicated land rover kit. This fault read exactly the same, when I run the tests again with the gearbox wiring loom left off altogether, so it looks like the brain in the replacement box was totally goosed, probably a broken or poor internal connection giving an open circuit condition. My son is into making and posting u-tube videos, so if its nice at the weekend, I will get him to do a quick video of me removing the brain from the old gearbox on the bench. With the box out oil drained and the sump off, its literally only a five minute job, when you know what you are doing. Don't know if I can post such a video here, but if not presumably I can post a link to it, or failing that drop a few hints as to where you may find it.

Ok folks, this post has not quite played out as I imagined, but I did promise to come back and let you know the outcome, so please see below The TCM, brain, or megatronics pack, can indeed be easily transferred between gearboxes, It took me around half an hour to remove the unit from my old gearbox, and around an other hour to swap it into the replacement gearbox, which was already fitted in my car. It was an easy enough job, even lying on my back under my car on my gravel drive, in fact it took me longer to fill the gearbox with oil than it did to swap the brain! The good news is that my car started of the key and now drives and changes gear as if it has just left the showroom. So to recap the original fault, with my car was a blown torque convertor, and I obtained and fitted a secondhand gearbox, but the car would not even start because it refused to see and or communicate with the megatronics control unit in the gearbox, and therfore did not know it was in park. I tried 2 different professional grade code readers, one of witch was dedicated to Land Rover vehicles, but neither could see and or communicate with the control module would. Not wanting to have to take the gearbox out and source an other I elected to take the TCM out of my original gearbox, and fit it into the replacement box. As soon as I did this my car started and now drives 100% Yepee! I do feel a bit silly speaking only to my self on a forum, I am pretty sure that's not how they are meant to work, but hopefully someone else may find the post useful.

Further to my original post, I have tracked down a video on line which confirms the electronics are indeed in the gearbox, and can be both accessed and replaced with the gearbox in the car, which, is great news for me. The video explains that when you fit a second hand gearbox to this model, the car basically rejects it, as if it were a failed organ transplant, and one option is to take the brain from your old box "if it is still functional" and fit it to the replacement, when thereafter the car will accept the replacement gearbox as its own. This has given me glimmer of hope, and I will swap over the electronic brains " It does not look like a big job at all, maybe a couple of hours work" and come back to let you know if this option works.

Hi folks, let me start by saying I am new here, and indeed to the concept of vehicle owners forum's. So please take it easy on me if I do anything wrong! I have a 2008 Range Rover TDV8 3.6, which I have owned for around three years, I have done a lot of hard miles in her, mostly relatively heavy towing at times very near to the vehicles maximum train weight. My problem is the vehicle began to lose drive, shuddered, behaved like the clutch was slipping and brought on various dash warning re gearbox failure. It did continue to drive despite towing 3.5 tones in heavy snow conditions, and luckily it did get me home. Given that it has done 175,000 miles, I accepted that the torque convertor had eventually given up "it had been shuddering and vibrating for months" and that the subsequent metallic fallout had most likely taken out the autobox at the same time. Being the practical hands on sort I am I sourced a replacement box and torque convertor from a very reputable local dismantler, and spent the weekend lying under the vehicle swapping out the old unit with my replacement "remind me not to try that again lying on a gravel driveway" Once fitted I tried to start the vehicle and nothing, it would not crank, I added a wire to the starter energizer terminal switched the ignition on and powered up my wire and the vehicle started, confirming to me it did not know the box was in park. Once started the vehicle would only drive in backup mode ie 3rd and reverse. I rechecked all gearbox wiring and all was in place clean damage free and secure. I hooked up my code reader and it communicated with the vehicle fine, but refused to see or communicate with the TCM "which I believe is in the gearbox on this age and model" I persevered for hours double checking, and I even called in a friend with a dedicated landrover diagnostics and it confirmed no coms to TCM. Yesterday I had a brain wave and cut free the gearbox wiring loom from its cable ties and was able to reroute it and pull it down far enough to be able to plug it back in to my original gearbox, which I had dragged back under the car. When I tried the car started of the key and the diagnostics were able to speak to the TCM in the old box without issue. Given the above it appears I spent the best part of 30 hours fitting a gearbox with a faulty TCM hence the user name 2gumpy! So there are 2 points to this post one is to warn anyone out there contemplating fitting a replacement auto box, to pull down the wiring loom and plug it into the replacement to check it, before crippling them selves swapping it. and to ask does any one know if you can change the TCM in the gearbox with it in place, as I really don't wont to have to do the whole job again, my aging bones are complaining enough having done so once. Please please tell me this can be done.