I changed my buddies u-joints front and back but have a squeak still? So I took out the whole driveline and jacked the truck up for a look, I discovered that the squeak stopped. So I was wondering what it could be? The yoke is lubed with tranny fluid, but was curious what that rubber ring was around the slip yoke? Is there any way for that to go bad? Is it replacable or do I have to buy a new yoke?