Whilst under the car I noticed a black line of something where the prop joint is. I had coated the tunnel in Dinitrol before installing the prop so the brown stuff is just dinitrol. Should I be concerned about the black line? It does look like grease and certainly lines up with the prop joint. Is the joint losing grease and should I be worried?
Propshaft with line of what appears like grease on the inside of the tunnel which is itself coated with dinitrol.