Got an 2006 Liberty, I'm putting new u- joints in. While I was removing the drive shaft, I noticed a rather large counter weight off to the side of the differential, well at least it appeared to me to be a counter weight, what is it and what does it do? Next question, I put MOOG u-joints in and they come with a flat style grease fitting, so I bought the pointy adapter for my grease gun, now I have grease going everywhere but in the fitting and suggestions.