It helps to provide model year and model (LT-LS) current mileage and what country are you posting from.I have lost 2nd and 6th gear it did throw a code p2714. I was just wondering if anybody else has had this problem and if so was it just a solenoid or am I looking at an overhaul of the transmission
This is an old post but just happened to stumble across it when chasing down a no forward condition with no codes present. This is a 6T40 Transmission, initially I had reverse and no forward gears so I switched my pcs 1-2-3-4 solenoid with my pcs 2-6 solenoid to see if I had a bad solenoid, after switching I had forward gears but got the code P2714 as mentioned above which controls 2nd and 6th. I then replaced this PCS 4 for 2nd and 6th gear and transmission runs perfectly normal. Just wanted to emphasize that the transmission does not need to come out for this common problem. For code P2714 simply change the PCS 4 SOLENOID (2-6 solenoid) which controls 2nd and 6th gear, other issues can cause this but most often its just the solenoid. Same as if you have reverse but no forward or slipping forward it will be the PCS 5 SOLENOID (1234 solenoid). For those wanting to give it the old college try, the solenoids are located under the plastic cover under the hood, front driver side. Remove cover, unplug 3 electrical connectors, [email protected] left and [email protected] bottom right, remove (12) 10mm bolts on the tecm, remove (3) 7mm bolts on the tecm, if you made it this far, this site will help. Gears Magazine | Understanding GM 6T40 SolenoidsMost likely a solenoid failure based on your description.
Trans has to come out regardless and case split if this is the case.
I would recommend a dealer perform a full diagnostic though before proceeding.
A trans shop generally will just condemn the whole unit so I cannot recommend that course.
Try one thing before proceeding......disconnect the battery (negative end) and leave headlamp switch on for an hour or so. This is the automotive equivalent of a 'reboot'.
Turn headlamp switch off and reconnect the battery and go for a drive......you may find normal operation returns.......can't beat the price if successful.