What Are You Doing To/With Your Car Today?

Got the rear back in today with the help of my 13 year old son. He was the jack man. It took some time but we got the pig in. I put the axles in and filled the rear with synthetic gear oil and limited slip additive. I even purchased the right gear ratio tag and sure grip tag. All I have left is the speedo gear in the trans and putting the drive shaft back in. Never done a speedo gear before. Is it difficult to do?