Rear end noise, anybody know what this is?

Too many beans!:B sorry can't resist with your choice of words in the subject line. :W

You should be able to pull the plug and see the ring gear. Stick your finger in it and feel the gear. Careful, because if it is bad, you can cut your finger on the worn sharp edge. Assuming you can lay under your coach safely with one wheel off the ground, Put it in neutral and spin the wheel with your foot, while you feel the gear. My diff made noise off throttle, but for the most part sounded OK on throttle. I had a couple of chunks missing from the ring gear teeth. A very hard shift from 4th to 2nd broke teeth. If you can shine a flash light in the hole, look at the wear pattern, it should be centered on the teeth. If the carrier is bad, consider installing a tru-lok carrier. It is a much stronger carrier than OEM.

rgatijnet1 wrote:
It could even be a bad U-joint or a bad carrier bearing.

My thoughts exactly. It's pretty rare for a diff on these beasts to go out. It might happen but, of all the folks I know that RV for a zillion years now, not one, on many brands, styles, types, sizes and more coaches, we've not seen one differential go bad. It doesn't mean it doesn't happen, it just means it's really rare.

I too would look at that "carrier" bearing, otherwise known as the "center support" bearing between the drive shafts. Also, put the rig in neutral, support the tires/chock them so the rig cannot roll in any direction and, lay under there and twist all those interconnected drive shafts back and forth to see if it's possible you might have a bad or, series of bad u-joints. Just a thought here. Good luck and post what you find please.
Scott

zman-az wrote:
One thing I would not do is drive this thing around. If you do it could leave you stranded and cost even more to fix.

Boy I'll say. My diffy horror story

Doubt its the u-joints. Bad u-joints will make a clicking sound and change with RPM's.
The problems is most likely in your rear differential. It could be as simple as a worn bearing or bad gears (although I think your gears are fine). Either way the rear end will have to be taken apart. Anytime you take a differential apart there is huge labor costs as the gears need to be properly re-installed with shims. Any one can rebuild a differential, but getting proper backlash, gear mesh and inch pounds setup properly on the pinion takes a "great" mechanic with the proper tools. If its under warranty take it to Ford. If not and you know a mechanic that does a good job then take it to him. I would guess a minimum of $300 on labor plus parts. If one bearing is bad just best to replace them all as installing the bearings is the easy part, again the labor is in the alignment.

One thing I would not do is drive this thing around. If you do it could leave you stranded and cost even more to fix.

It could even be a bad U-joint or a bad carrier bearing.

Bird Freak wrote:
Usually means bad pinion gear.

Has to be both. You can't replace just the pinion. You have to replace both ring, and pinion, As they are a set, Lapped together, never to be seperated.

I had that on my GMC Envoy. It was the rear pinion bearing.

Terryallan wrote:
Easy fix really. New ring, and pinion. Less expensive than you think

Plus all new cups, bearings and seals. $2400 at a Ford dealer.

Usually means bad pinion gear.