To start, I have had great success using these gearboxes and find it interesting that they appear to be higher HP rated to output bore than the cast iron units. But if I had to complain, please tell your supplier you must supply flat washers with the bolts and lock washers.

Lock washers alone are not effective over a slot on the motor mounting flange. Now, this hasn't been a issue for me as I've always installed them in my factory and we keep flat washers in stock. But if I was in the field and a Home Depot or Lowe's is not nearby, I'd be a little perturbed.