I have a 98 windstar that has been great till yesterday. The transmission started shifting from o.d. back to 2nd and back up then straightened out. Today I drove 35 miles and stopped for awhile ,when I started back home it is in 2nd gear and won't upshift. I was told this was failsafe mode and probably an electrical problem since there has been no slippage and 1st ,2nd, and reverse work great. Any advice? I'm disabled so cash is a problem.