Tranny won't shift

ok so heres the scoop first....i was goin on the highway and all was good, i exited, took off and before i know it, im at damn near 3000rpm and not shiftin, i have to let off the throttle for it to shift, i took it down to a buddies shop and it gave a code that the 2nd gear ratio was off...but i got back in and it was fine, then i did some stuff to my truck and it did it again.... all im lookin for is what y'all think is wrong or what you think ill spend....

thanks


oh yea the codes are p0732 and p0781