Santa 06 has P0734

What is your question?

Hi Yesterday I turned up my santa 06, it worked but as I set the transmission hand lever in R and pressed the paddle the car didn't move reverse back however the hand lever transient smoothly between P, R, N, D, and on D the car moves forward. Furthermore when I but the lever on manual mode it shows (3) on dashboard instead of 1 or to. Actually the car stuck in gear 3. I checked the fluid level, it was okay, but full of bubbles. I got it diagnosed by OBD II So it showed P0734. What shall I do? Thanks

How long has your 2006 Hyundai Sonata had this problem?

Two days