Just got the car back after a tranny rebuild 500+ miles ago. Current problems include:

When driving in 4th and I shift to 3rd the car responds as if in neutral (i.e. no noticeable slowing as would normally happen)

When starting the car, the Power light flashes 16 times. Haven't done the diagnostic yet, but plan to tonight.

When driving around, the 1st gear light intermittently flashes for no reason.....

Any help you guys could give me would be greatly appreciated