Differential or axle bearings problems?
I took my 2007 WK 5.7 wheeling the first time up Cherokee trail/Poudre Canyon/NE Colorado last week. It did awesome, but I did stop a couple times to let it cool down. The fans were kicking on hard like I was running my AC but I wasn't. I also saw a "transmission over temp" warning come across my dash. So I took a break and had lunch.
I drove my jeep back home 60 miles and left it on the driveway. When I cleaned out all my gear and moved it into the garage I noticed oil on the driveway. Looking underneath I saw that my rear differential cover had oil along the bottom and a nice ding where I must have hit a rock. Checking the level with the drain plug out, it was low...but only about 1/2" below.
I needed to run to get some differential oil, so I took the jeep with the windows down and could hear a low, intermittent rubbing/vibration/humming sound. I thought it was a loose plastic fender liner rubbing, but everything was clear. I took the cover off and found that the bolt was loose near where the damage to my cover was and the silicone gasket also had some damage. I plan to scrape clean the old gasket, pound out the dent on the diff cover, reapply a new silicone gasket refill with new diff oil...which was due anyway.
Is the intermittent rubbing/vibration/humming noise normal when low on diff oil or if that oil got too hot? There was no metal shavings or anything damaged observable with the cover off. I asked a mechanic friend of mine and he said maybe the noises are my axle bearings and that they may need a once over since that trail was pretty difficult and worked the jeep pretty hard.
Any advice guys? Thanks very much in advance!