2000 Expedition transmission problems

[naynay170]

Ok I hope I can get some answers.When I get up to about 50 mph it is like it slips out of gearbut I can mash the overdrive button on the end of the gearshift and the car will pull but it want change gears and the od light fashes on the gearshift, so had it checked and they said it was the shift selenoid weel got one from the ford place my hubby put it in and it worked fine for like 2 days and now it seems like when it warms up it stops pulling around 50 mph so I have to do the overdrive button again if anyone knows what is wrong or what is making the solenoid go bad I would appeciate it.
Thank You

[rhandwor]

Ford had some problem with the transmission coolers. Have him use an air compressor and blow through the cooling lines with both of them disconnected. They use a lot of fluid make sure it is full and he used the proper fluid. I think they use Mercon at this time. If he used fords old fluid do a complete change. Check the manual at the parts store and buy the proper fluid. My 1997 F-150 with an E40D used about 14 quart when I changed my solenoid and cleaned the valve body. Its probably just low on fluid.