I drift AT with a controller. Gearbox is irrelevant I promise. With a properly tuned LSD the car will prefer to maintain high RPMs when all the driving aids are turned off. Veteran secret.
My recommended button mappings for drifting are Gas(R2) Brakes(L2) E-brake(x or circle) Steering(Left Stick).
Most important tunings: LSD (Acc:60 or maxed, Torque:60 or maxed, Braking:5 or minimized), Suspension (Spring rate and toe angles being most important), Tires (DON'T MIX-MATCH TIRES and don't go higher than Sports Hard. I only use Sports Hard on cars with more than 700BHP)
Power over and Feint techniques are great techniques. Ripping the e-brake helps if you're having trouble drifting long MR vehicles.
Try to use light vehicles... 1400 Kg or less, although I've drifted a Toyota Tacoma and a GT-R just fine.
Turn off ALL of the driving aids. Every single one. If you're using a controller have your sensitivity between 1 and 3. I use 1 personally but 3 gives you "prettier" slides because of the dramatic over-corrections.
Experiment with different drive cameras. You drift differently when your perception of the road changes. I drift best with the "over the hood" view.
After that it's all practice and helpful tips from people who don't suck. Inbox me anytime on PSN. l2oI that's a lower-case "L" the number "2" lower-case "O" and capital "I"