At our school bus shop our manager buys the best of everything, he thinks. We use that black synthetic grease on everything. We also go through a lot of wheel bearings. Some of it is over tighting. But what I have seen is after a year or so the grease breaks down and acts like oil. When we pull the caps, this nasty looking crap runs out. I would like to see a heavyer grease used, but you can't convence the boss. He can't hear anything while he's patting himself on the back!! LOL. Joe