auto tranny problems

okay people- I have some questions i have a 93 escort gt 1.8 175,000 miles.The transmission shifts ok in the warmer months(wisconsin weather)now that it's starting to get cold the transmission keeps shifting in and out of overdrive at highway speeds. I'm going to check the line pressure is there any kind of sensor or switch that could be going bad. A :banghead: t 70 mph. i'm running 3000 rpms then will drop to about 2600 rpms.it will do this for miles until it finally stays into overdrive. Anyone have any ideas??

Check the parts store and see if your tranny is eqipped with a 'vacuum modualor'. These will cause the conditiond you describe. To look yourself see if there is a vacuum line running from the manfold to the tranny. If so you should see it.