Hi Folks

I'm looking for a little advice. I have a 2003 4.4v8 HSE with the ZF box & 120k on the clock. The transmission has an intermittent problem that is causing the box to shift very roughly. Sometimes it's so bad it almost feels like someone has hit the back of the car.

Sometimes I can start the car from cold and the the box will shift badly for the entire journey - other times it will start from cold and it shifts perfectly. The shift never improves or gets worse during a journery - it either works properly from the outset or it doesn't. I don't get any messages coming up on the dash regarding the transmission.

I've taken it into a local auto box specialist who were recommended by my local Land Rover specialist. They have opened up the sump & all is fine in there - nice clean fluid - no bits which I expected as the filter & fluid were replaced about 20k ago.

They've plugged it in & are getting some strange temperature readings from the gearbox (-21 degs!) which caused them to suspect the gearbox temp sensor. They've since tested this & the harness & can't find a fault which is now leading them to suspect the ecu.

At this stage they aren't fully convinced it's the ecu so are reluctant to get a new ecu due to the cost until they're sure.

Any thoughts or suggestions wold be greatly appreciated.

Cheers

James

I would strongly recommend that you take resistance measurements at the ECU end of the PTC sensor wiring. Measure between pins 12 (white/red wire) and 22 (black/red wire) on the plug furthest away from you when you're stood by the side of the car, maybe taking one reading when cold & another when warm and comparing them to the graph.

Click image to enlarge

Click image to enlarge

Click image to enlarge

Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated