Really hoping for help with my car's transmission...?

I have a 98 Ford Contour SE 4 cylinder automatic that just last night started hesitating when shifting from all gears. I had this happen in the past and my dad fixed it (has since ped so I cant ask what he did). It has about 140,000 miles and the transmission fluid levels are good. I noticed the fluid color is reddish brown. Yesterday during the day I drove it and it was completely fine, last night when I tried to drive the overdrive light started flashing and it started the thing where it revs up then jumps and shifts when you drive. Anyone have any idea what could be going on?