Isn't there a legendary problem where a dealership replaced an entire transmission because of an aftermarket bulb in a taillight? Not sure if this was a LR3 or 4 lol.
The story is basically correct - was an early LR3 back in 2005 before LR Service understood that a bad tail lamp bulb / non spec tail lamp bulb would cause the computers to indicate a transmission concern.
The transmission tie in to the tail lights / brake light switch circuitry is a result of the downhill assist feather that creates an automatic engine braking function and braking due to the anti-skid anti-lock brake system.
Downhill Assist would tell the engine to throttle back and perhaps operate the brakes as well. but regardless, the downhill assist system told the brake lights to illuminate when there was a speed reduction or retardation.
This engine computer tie of the brake light circuit, the throttle circuit and the transmission computer would result in a tranny trouble indication from an off spec bulb. At that time, no other manufacturer had a downhill assist system and hence it was not well understood by anyone. It is better understood now by the vehicle manufactures as now shows up on many makes.
Apparently the new LR3 owner had replaced a burned out LR factory tail light bulb with an off shore bulb but had neglected to mention that to the dealer. IN any case, the tranny was replaced by the dealer under warranty as indicted by the T4 display but the trouble persisted. When LR ultimately discovered the off spec bulb, they did want give the LR back to the owner until he paid for the replacement tranny.
Land Rovers position was that tail light bulbs are provided free under warranty and the owner has violated the warranty conditions.
The 4's apparently do not suffer this concern as software was subsequently changed as well as the tail lights - incandescent to LED.
Off subject, those LED lights look quite good - better than the stock LR4 tail lights in my opinion, however I prefer the look of my factory LR3 tail lights as LED is in my opinion not quite right yet - usually too bright at night and generally too small an illuminated area which matters in mud and snow. Also the LED are not as hot as incandescent and hence tend not to melt the snow off.
My only wish was that LR has installed the brake light function re the NAS spec vehicles in all four bulbs, not just the top two - kind of USA pickup like. One burned out brake light filament means you lose half your brake lights instead of just a quarter of them plus it gives the locals "cause" to pull you over.
Needless to say, I have LR spec 12 volt 21W 5W dual filament bayonet base bulbs in the four top locations but I did install LED for the backup bulbs. That does not seem to cause any problems and at night, the LED bulbs provide a higher degree of illumination to the backup camera, a bit of a plus and all looks stock.