Hey yall. My buddy brought me his 01 f250 it wont shift out of 1st then if it does it slams into second then the rest of the gears are fine. This was after he over heated the tranny last sunday in the mud while he was at work. He was low on fluid so i had him add some. I shift manually thru the gears it seems to work could this be a vacumm or a clugged filter