So I am doing some transmission work on my 1950 Farmall Cub. One of my coworkers, I work at a Diesel repair shop, informed me that on his 07 Harley Davidson he switched from the stock gear lube to a full synthetic gear lube. He told me that he came home from work one day and found a big leak coming out of his pinion seal. He took it apart and he found that the ball bearings races had come apart and all the balls were in the bottom of the transmission. So can a full synthetic gear oil cause bearing failure? It just does not make sense. The coworker explained that this happened because the oil was to slick and instead of the balls rolling they just slid in the bearing? So I am just curious is this fact. I am replacing all the bearings in my 50' farmall and wanting to fill it with a good synthetic. I know it is overkill being that the transmission is a three speed and a sliding gear type, but I am curious.