Hyundai Repair: engine codes hyandai9, bullitin, solenoids

Question
2000 hyandai sonata 75 k miles auto 6 cylinder

2 codes p0755 & p0765

755 shift solenoid b circuit & 765 d circuit solenoid malfunction

just need to know if this is an internal transmission repair or something I can replace externally?  the car won't shift to 3rd gear. I can do a lot of the work myself but finding it hard to find where these solonoids are--a notice hyandai had a service bullitin on this code--bulletin #'s : 0340006 and : 133 but I can't find anywhere on how to fix.  Can you help?  thanks Jan

Answer
The TSB you reference has a repair description in it.  If you don't have access to the actual TSB, I recommend you get a free account at www.hmaservice.com (requires Internet Explorer).  Actually, TSB 03-40-006 has been updated several times and the latest version is 05-40-006.  

I doubt you have the capability of testing the solenoids like it describes.  The two major issues are the internal wiring and the solenoids themselves.  I'd recommend having a look at the external wiring, and if nothing is wrong, replacing the internal wire harness and solenoids in question.  They're located inside the cover on the front of the transmission.  You'll need to remove the radiator, the cover, and the valve body to do this work.  The solenoids in question are the UD and OD solenoids.  The TSB gives a picture of where all the solenoids are located and details as to which codes refer to which solenoids, as well as part numbers for the repair items you'll need.