I've been smelling gear oil so I thought I would climb under the truck and check things out. My rear passenger side brake cover is soaked and the rear differential fluid is low. I've done the job before on my old Wrangler but don't think I want to put myself through that again. My question is if/when I pay someone to change the seal should I have the do both? I know on my Jeep I had to remove both axle shafts so it was just as well to replace both.