Hello people.
I'm new to this part of the FTE site, but have received lots of help (and hopefully given some) for my '94 F250 7.3 turbo. Anyway, we have a 2003 FWD explorer with the 4 liter and about 91,000 miles. I've got the rear hum occurring starting at about 30mph and getting louder as speed increases, under load or not, and have recently rotated the tires. I was thinking wheel bearings, as one was replaced under warranty a couple or so years ago, and there is so much talk about it on this forum. I checked for any play (up/down and side to side) in the rear wheels this morning and cannot perceive of any on either side. When I inspected the rear driveshaft it was tight at both ends. After that long introduction, here is my question...in the center of the driveshaft there is a rubber boot similar to one you'd find on a cv joint. Should there be any play in this joint? Although not terribly sloppy, I can definitely feel enough play that I'm thinking this could be the source of my noise/vibration. Does anybody have any thoughts on this?

 

That is a slip joint, give it a couple of squirts of grease in the zerk fitting.

 

If that joint was out of spec, you'd get a vibration methinks.

The hum is just to let you know you'll be having bearing work done on the diff as soon as the hum gets so loud you can't stand it.

 

Thanks for the quick feedback. To share some things I learned this morning..., I talked with the dealer (who'd replaced the left, rear hub and bearing assembly) and the tech said there is some normal movement in the slip joint. He also said some up and down play in the stub shafts coming out of the differential is normal. We're heading to Maine in a week and I think I'm at the point I don't want to drive 4 to 500 miles with the racket. Besides that, I'd hate to have it fail and the family and I end up walking on I95...

So I made an appointment with the dealer to diagnose the problem tomorrow. I've pretty much narrowed it down to the right rear. My only thought is that I can replace the whole hub and bearing assembly for a lot less than I'll pay the dealer. I've seen on other posts that I can just replace the bearing, but if I opted to replace the bearing and hub assembly, is it a pretty straight forward remove and install? Or do I still need access to a press? Any help is much appreciated.

 

We kind of had the same problem with our 03' Explorer, and it ended up being a balance weight had fallen off the drive shaft at the rear axle end of the shaft.
For a quick temp fix, I taped a couple of washers to the head of a hose clamp, and after a couple tries to get the weight right with the washers, no more vibration/noise! It really worked great. I also made sure that I positioned the clamp with weight over the location where the old weight was.
Hope this is all it is for ya, good luck!

Mike