[apalrd]

WCP dog gear is 7075 Aluminum. Hardenening spec not listed on website. It's 5/8" hex as stated earlier.

AM dog gear is stainless steel. No alloy spec on website. It's 1/2" hex. Some use a 4/40 bolt, others use a roll pin to attach the dog to the shift linkage. We've always gone with the roll pin variant for the comp bot and never broken one.

Maybe 7075 isn't up to the task? I've never seen an AM dog break like that. Every one I've seen break is because of the bolt/pin breaking off inside.

Shock loads can be brutal on drivetrain components. Just sayin. The dog can certainly handle the torque loads of the motors, I would guess indefinitely. But shock loading (especially high-speed impacts) can subject drivetrain components to many times the load the motors are capable of. Just think about the time (acceleration) required to get up to speed under motor power, vs the time (acceleration) required to get back to 0.