Dean N Breanna Close

I have r33 gts-t with a few mods. It has an auto gearbox which I think is f**ked. It's like I only have first and second. No third or fourth. When in drive it's like it will just slip then go into seconds. The oil does have a slight burnt smell so I'm thinking maybe I have burnt clutch packs or something, but I'm really hoping it's something more simple like a shift solenoids, or a sensor or something.... Help!!!