Just had two rear leaking hubs replaced with used ones that were represented as being tested and good. However after getting them I noticed that one hub bearing spun freely while the other had considerable roughness. Does that indicate a "spent" hub, or one that lacks internal grease?
I decided to bolt down both new used hubs anyways. After driving a few miles I noticed one side was leaking a bit. Drips were coming off my left side rear brake backing plate, creating small wet spots on my inner wheel.
My first thoughts were that that was the one questionable hub leaking, but then I also thought that the leaking fluid seemed too thin to be sealed hub grease, but seemed more like gear oil. I asked a mechanic, and he said that the leak was probably just a bit of residual gear oil that squeezed out past the o-ring after the hub was bolted down. Seemed like ok advice, but then why only the left side leak and not both sides?
I continued to drive it for a few days, and noticed the leak went away as the mechanic suggested it would. I have rechecked the diff. fluid level and it is still full.
Now a few weeks later, I noticed a few things. One was after I sat a few people in the back seat, I experienced a loud tire noise- a kind of "whirring" sound that stayed consistent until it was just me driving again. I have also noticed a decline in MPG.
Could the "whirring" sound and poor mpg be caused from a "dry" hub? I'm thinking maybe not, that a dry hub would make more of a loud grinding type noise? If I'm wrong and that a dry hub would still turn quietly as long as there isn't much weight in the vehicle, it seems to make sense that mpg would be affected as a dry hub would have more spin resistance?

 

A hub should be firm and quiet when you spin it with some resistence. What I have found anyway. Did you put new hub seals in or use the old ones.? Your leaking sounds like diff oil. Does it smell like diff oil.? Easy to replace as you know. Some have had good success with white shepard additive to restore those seals but I have never used it. Are you getting the Amigos? Bad bearing will really have a negitive effect on the sensor. Just some thoughts.

 

Yes I did use new o-ring axle seals.
Remember the leak went away and has since stayed away for over a week now, so I'm guessing it's over and the mechanic was correct in saying it was residual fluid from the hub install (tho I still have doubt since only 1 side leaked.)
if my sniffer and eye is correct it was def. gear oil leaking out
Funny you should mention the three amigos. From time to time I get them, but they go away quickly- usually after the first key restart. They have not come on for a few months- but just this morning they did appear, and like usual they dissapeared after the first restart.
Can anyone comment on the whirring tire noise and decline in MPG?