Have a 95 Dodge Diesel with automatic transmission. Last year while driving felt like TC slipping. Engine would rev from 2000 to 2500 rpm but speed would not change. Would happen intermittenly. Mechanic changed OD selonoid-no help. Then he rebuilt transmission-no help. Then this summer transmission was fine went to SW from NY. Came home and problem started again. I changed out speed sensor and transmission thermostat-no help. Changed oil-no help. I did figure out that this problem only happens when outside temperature gets below 60F. That is why it didn't happen on SW trip-temperatures were above 80 always. Then on trip to Pa it started because it was cool. Next morning it was above 60F and no problem for 200 miles. On way home the evenig got below 60f and it started again. Anybody have any ideas of what can cause this. Even when it happens it will happen only once or twice over 20-25 miles then other times it will happen 5 or 6 times and then go away for 50 miles or so. Driving me nuts!!!!!