Pontiac Repair: 1994 pontiac bonnerville 3800 new trans stuck in second, alternater, solenoids

Question
i just had a new transmission put in my bonnie for $1600 but its stuck in second gear and i have codes p1640, p1650, p0312..
also just replaced fuel pump, batt, and alternater... two mech's say i need my trans rebuilt but i am broke because i just replaced all the above mentioned. the mech that installed my trans said its fine i have an electrical problem that is causing my trans to opperate in 2nd gear safe mode. please what do i do?

Answer
Hi there:

Well that is an electrically controlled transmission. It has 2 shift solenoids inside the transmission. If one of those solenoids is bad or if the power/ground is bad going to one of the solenoids it will be stuck in a gear and not shift. You are going to have to find out if it's a control issue going into the transmission or if it's a solenoid inside the trasnmission that's bad. If the trasnmission is new/rebuilt it should have a warranty on it.. They should at least honor the warranty on it and not just say it's not the trasnission if it's not the transmission then what is it?