The piston is actuated by a rod to the brake pedal, but there is no adjustment in it, its just a linkage.

An adjustment of when it goes from neutral to drive is what I'm looking for, as if I could adjust it so it went to drive when there is still a significant load on the brakes, it would accomplish what I want... i.e. the trans would engage before the brakes are released, and then a slow release of the brakes would let the machine slowly start to move.

I'll check to see if there is any other way to adjust that piston in relationship to the brake pedal.

Thanks for the response!