Same as title, I own a 2014 Corolla with 125k miles, automatic non-cvt transmission (U341E). Went to AutoZone to see if any codes appeared, none. It recently started slipping from 1st to 2nd gear. I bought the car at 105k miles, unsure of when the last time the trans fluid was changed, but I changed it about two weeks ago, threw some Lucas Slip Fix in there and changed the filter. No dice, after 350 miles it's still present. I read similar posts where the transmission control solenoid was replaced and it fixed their respective issues. AutoZone quoted me $50 for the part. How difficult of a DIY job is this? Am I better off taking it to a mechanic?
I would take.the vehicle to a quality transmission shop for a proper diagnosis.
Autozone is not qualified to do transmission diagnosis. They probably used a generic OBD2 scan tool which will not even pick up transmission codes. For that, and to do bidirectional testing of the shift solenoids, a professional-grade scan tool is required.
Take it to a good independent mechanic to check it out. (Not a dealer and not a chain shop.)
I agree with the others. Take it to a transmission specialist asap.
These things need to be dealt with immediately and you should have taken the car off the road. Continuing to drive a slipping transmission can destroy it and it may be too late already.
