Automatic Transmission problems of the 2000 Mitsubishi Montero

After ~ 2hours of highway driving the "n" (neutral) light flashes which indicates that the transmission has overheated. The car most be stopped ASAP to cool the transmission so as to not damage it. I am concerned that since this problem has occurred everytime I go on a trip lasting more than 2 hours of hwy driving am I damaging the car or causing a potential safety (fire/personnel injury) hazard!? I have taken the car to the dealer to search for a cause and solution but they found nothing. Is the transmission fluid compromised and therby causing this? in addition, this is an inconvenience when one is travelling. Being that I travel a lot I always have to be on the lookout for this problem. Aside from being a safety issue and potentially a costly repair issue it's a nuisance! flashing light ?.

Took my truck back to the dealer on 2/22/01 for engine light that came on. They replaced a leaky fuel cap and engine light went off. Told them when I call for service about the 2nd -3rd shift that was slipping in the transmission. The could not find what I was speaking of the first time. The second time I took it back for the same reason they then said that Mitsubishi had a letter stating that there was a problem with the 2nd - 3rd shift. The called the tech line and no one new what to do with the vehicle. They in turn wanted me to pay for a tranny flush, I refused telling them I had been instructed by a mechanic friend that this is not the problem, so I did not have that done. To boot they wanted me to pay for this (80. 00). !! when I called again about my vechicle doing the same thing I told them I did not feel the vehicle was safe to drive because driving a damaged transmission was not good, the told me that I was in no danger. The third time, they instructed me Mitsubishi could do nothing else to help me and I had to pick up the vehicle immediately. So now I am driving a possible damaged transmission and who knows what else will happen. I would like to request and investigation into this, the mechanic at the dealership told me other vehicles(montero's) have been doing the same thing as well not just mine. I believe this is Mitsubishi's responsiblity to fix this even if it means a new transmission!! if you would like to talk further on this problem please feel free to contact me at the given numbers. Thanks and have a great day. --- concerned consumer.