For those of you having issues with differential binding when tightening screws through gearboxes into motor plate and front belt housing, I have a fix. Take a 5/8" Forstner bit and remove some material from bottom of bearing pockets for differential in both gearbox halves and binding will disappear. the gearbox halves are putting undue pressure on both sides of diff through bearings as they can not seat into bearing pockets deep enough and causing binding when tightening screws.