e40d transmission trouble
 

I have a 97 f-350 dually with 4:10 gars and the E40D tranny. The "Over Drive" light on the Colum is flashing. Also the transmission shifts hard in 2nd gear but no other gears. I ran the DTC on my tuner and cleared a code for the transmission and drove about two miles down the road and it shifted in 2nd gear as smooth as butter. Then the "OD" light began to flash again and it started shifting hard again but only in 2nd gear. If anyone has had this problem and found out how to fix it please send some advise. Trouble code was
"P1728" Thanks Matt.