I have a VW Golf that recently refuses to shift into 2nd gear. Engine will rev, but will never shift. We took it to our VW dealer and he said the fluid looks fine and everything external looked fine. It’s a closed tranny so I haven’t checked fluids yet.
If I scan for codes will anything show up? Could this issue just be a sensor or is the entire tranny bad?
Thanks
Is the Check Engine light on?
If not, use a scammer/code reader that can pull pending codes.
Tester
Sounds like a scam! 
Didn’t have my glasses on. 
Tester
Let the one who is perfect cast the first stone! No stones yet, thanks for all you do @tester.
My guess, either the tranny needs a routine service, replacing the fluid w/new, new filter(s) if applicable, or a solenoid has failed. Start w/a code-scan using a code reader that is able to access the tranny-specific codes. This may require a trip to a VW dealer or inde shop that specializes in VW.
The reason replacing the fluid could work is b/c an automatic tranny requires a very high internal fluid pressure to create the force needed to effect the shift. The seals that contain this pressure can stiffen w/age, allowing internal leaks which prevents the fluid pressure from getting high enough. New fluid contains fresh seal conditioning chemicals.