I have had transmission linkage problems HDC failures and also Transmission faults with a 2006 LR3. I replaced the transmission fluid, but did not fix. I adjusted the cable linkage several times, but although it shifted ok, it never seemed to stay in gear after an undetermined amount of driving. The most obvious symptom was although it was in Drive at the center console, the D in the speedometer display window would go out. Then if un-noticed, engine would rev from a stop. Sometimes I could use sport and manual, but sometimes they didn't work.
Noticed that I could put pressure on the shifter and that could cause the D in dash to come back on. Release pressure and it might go off, sometimes staying on. When on, transmission worked, when off, no go.
So, during one linkage adjustment scenario under the truck, I noticed a couple wires in an electric circuit box behind the linkage cable connector. It seemed loose and partially separated, I reseated it, re-adjusted linkage, and all is well. The Speedometer display show the D solid and hasn't went out since. No HDC faults or Transmission faults driving across the state during a snow blizzard.
Can anyone speak to whether that electric circuit controls the dashboard display of gears? PRND, etc? Seems they all need to be in sync, linkage is adjusted, have a D on the center console lite up and the D on the Dash display. If Dash display D, doesn't sync, you get the transmission fault and the transmission is disabled or in neutral.
