I voted 'yes' but my answer is only part of the time in the stroke.
As soon as I see that I will be hitting a backhand and not a forehand I do this:
- turn/coil upper body & shoulders and change grip with left hand (off hand) as I turn
- As the ball gets closer before bouncing, I turn my shoulders a bit more and pull back my racquet a little further back and down. At this point the hitting side of my racquet is more or less facing my back fence. It is at this position that I pull the hardest with my left hand/arm. But it still isn't with a lot of force compared to the force from unwinding my shoulder/torso and stepping into the ball.
I think i pull harder on backhand slices, but in a different direction, as I am about to swing forward.