m0766 Mazda - why is my mazda 3 2004 transmission not shifting into the 3rd and 4th gear

Question

my mazda 3 2004 automatic is not shifting into 3rd and 4th gear , after changing the dirty transmission , its showing AT light on. the ECM is report says the shift solenoid is stuck on d. pliz advise

Answer 1

have you replaced the transmission fluid? the solenoid is stuck open that means the valve is not closed due to dirt contamination

if replacing the fluid does not help you may to replace solenoid or the whole valve body if the transmission is slamming gears and grinding and there are metal flakes or piece the transmission fluid and pan you will have a bad transmission and needs to be replaced.

the transmission pan will have to be removed to get to the solenoid in the valve body 

Mazada 3 2.0 below (not sure what model car you have since it was not mentioned)