Well I had it in 4 hi and I had the engine at like 4000 or so and it would't get up the curb.
So I figures if I put it in 4low that I'd get twice the torque, and if I had it at 4000 rpm I wouldn't have to worry about flying back into something once I got up. It worked out just like that.
I also figured th band might have been the front tires engaging in 4 low because if I remember correctly I took it out of 4low. So when I engaged it, it has to move a few inches to engage the front wheels. Wel, it didn't move until I floored it, so the bang occurred because of all the power being transfered.