I recently returned from an 8,000 mile trip with my excursion and travel trailer. while i was about halfway through my loop of the country i stopped at a dealer and had the engine oil changed and the rear end serviced. Today i checked the fluid level in the rear end, and it was incredibly low, took 2 quarts to fill it up, and there are no signs of it leaking.

I pulled out the paperwork from the "servicing" and they listed only putting 2 quarts of gear oil in it.

So i drove this thing 4,000 miles fully loaded pulling a 10,500 travel trailer thru the deserts of Arizona, California over the mountains in California, Nevada, Idaho and Wyoming all with half the oil it was supposed to have.

how bad was this?

 

The only way to really tell would be to unbolt the cover and visually inspect it. That's harsh though, I'd call the dealer and give them hell. Improper service that could have damaged your rear, I'd think they'd be responsible.

 

Obviously not the greatest of situations. The differential still had a little oil, but the level of the fluid was probably lower than the hub bearings. They may have been damaged from heat.
If it was me, I'd pull the cover on the diff, drain it, pull the diff, and inspect the carrier bearings, Then I'd the pull the hubs, inspect the bearings, and replace the back hub oil seals and the outer o rings,
and replace any bad bearings along the way.

You may have lost the fluid from leaking hub seals. or the dealer did not make a good seal on the cover. Pull your wheels and check for leaking at the back of the hubs

 

 

I've never done more than a fluid change to any rear end, how hard is it to pull the diff? and what would i look for in the bearings?
Do i have to pull the wheels and axles to do this?

 

 

It is not terrible to pull a diff. but you need a torque wrench and strong arms. Most people just pry it out with a bar after removing the axles, cover and bearing caps. You have to keep it absolutely clean while it is out, and any shims and spacers have to go back exactly where they were before.

What to look for in a bearing? After absolutely thorough cleaning, the bearing cages should have no damage and still retain the rollers well There should be no obvious wear to the eye.. The rollers should be smooth and mirror bright all across the roller. There should be no matte surface or blue color on the wear surfaces. The rollers should have no scratches or pit, and should spin freely by hand with no feel of grit.. The races are the same. Smooth and near mirror bright over the entire bearing surface with no matte areas, no marks from rollers impressed on them, and no blue areas at all.

Matte surfaces are caused by normal wear (or dirt contaminated oil/grease) and indicate the bearing is nearing it's life. Straw or blue colored lines or areas indicate that the bearing has gotten hot from lack of lubricant. The colors means it got so hot that the steel has lost its heat treatment and has gotten brittle at those locations. Then they will fail when the bearing shatters on these brittle areas., usually just at the worst possible time.

 

well, that sounds like fun....

would i have to pull the pinion out as well?

 

Well, maybe. If you had very little or no oil in there it would be a yes. But you had enough oil for the main gear to sling around.

Start progressively. Try the hub bearings first. If they show no signs of trouble, then clean them, replace the seals and put them back in and go. The good thing is you still had some oil in the pumpkin, so it was slinging it around the pinion and inner bearings, so if the hubs are still good, the other bearings are probably good, too.