Land Rover Repair: Transmission Overheating Light, tranny fluid, inter cooler

Question
John - The transmission overheating light comes on on my wife's '99 Disco II when the outside temp is over 70 - 75 degrees and she drives in start/stop traffic or turns on the A-C. The dealer serviced the tranny less than 5000 miles ago, and she's had no problems until the weather got warm. The engine temp is fine - mid-range always. We've checked both the transfer case and tranny fluid levels and they are fine. I had a bad fan relay, which kept the electric fan from kicking-in and I thought that was my problem...it wasn't. Any chance that it could be a bad sensor?...any other ideas.

Thanks

Answer
Hi Tom,

its possible that a sensor has failed.  Its also possible that you may have an inter-cooler problem.  This is the smaller radiator in front of your larger rad.  I believe that the tranny fluid is cooled down with the inter-cooler rad and your oil fluid is cooled down with the larger radiator.  

You mentioned that you had problems the electric fan and perhaps some trouble started from that moment on.  You should have the inter-cooler pressure tested to see if there is any blockages or fine leaks. Just to be safe, have both radiators pressure tested - you are already testing one...why not test the other...should be same price.

All indications point to either cooling process or temperture sensor fault.  Just make sure your tranny fluid is clean and at the right level.

Best of luck,

JohnMc