4L65E shift problems denali

[rigid]

Wife drove to work fine . 12 hours later coming home it ran 3500rpms to go 55 . problem is she was about half way home before calling . Fluid is not perfect but i have seen much worse . have reverse and takes off fine in drive .around 25-30 the problem starts . it will shift if you back off a second , but then get to around 50 and running 3500rpm . only engine codes are P0449 vent solenoid and P0455 purge solenoid . no tranny codes . temp gauge for tranny was around 150* . Had the check engine light on for a few months , but not sure if it was both codes or just one until today . checked all tranny related fuses under the hood . would either of the emissions codes cause such a problem ? trying to convince myself we won't need a new tranny ! thank you