I picked up this truggy and it has a V1 diff in the front and a V2 diff in the rear. I think the V1 has a black spiral gear and the V2 has the gold-ish color spiral gear? Both are 43T. No matter how many shims I put on the front diff pinion (between bearing and gear), the front diff binds. I took out the one small Phillips screw that could bind on the spiral gear.

Could this be due to the V1 diff currently installed?