[JohnDeereJoey]

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Because of miscommunication with the seller this mulcher had 1000rpm gearbox so with proper gearbox I believe it would work a lot better with less bogging down.
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I'm thinking the opposite...the wrong gearbox is resulting in the mulcher drum turning slower than designed...thus more torque.

 

[JohnDeereJoey]

It was indeed turning slower than it should but that does not automatically result in more torque. You would get more torque if input(1000/540) was reduced more by the implement gearbox. The drum holding teeths needs certain momentum to work optimally for its specified capacity and it was spinning basically half as fast as it should have.

This is interesting...it sounds like it is a question of 1) Will the mulcher will work best (at least momentarily) with higher rotational inertia? or 2) Higher (continuously available) torque? Put another way, where is the sweet spot between high rotational speed versus available torque?

Please post your findings if you decide to try a unit with the other gearbox.