I changed the oil yesterday at my sons house and after we jacked up the truck so we could inspect the brake pads, he had a floor jack and we still had to put a 4x4 of block of wood to get it off the ground so today I thought I’d fix that problem. So I got underneath the truck to take some measurements so I could make an extension from the frame to the jack so it doesn’t max out of height and I looked at the rear to the axle and found it was discolored meaning wet, not dripping or anything but was leaking. I thought the axle was a one piece cast like what I was used to but I guess not because the passenger side was totally dry so my question is, is there a seal that I have to replace or can I just seal it with something else I don’t want to take it to a dealer and not sure if it falls under a warranty item I just hit 40,000 miles any suggestions would be appreciated thanks