Rear end whine - to fix or not to fix
 

Hey all - my 04 has a noticeable whine under throttle load between 45 and 60 MPH. From what I've read and based on the discussion I had with the tech at the diff shop, my pinion bearing is very likely bad. They quoted me $650 to rebuild the whole rear end which I thought was pretty reasonable. To note: There are no fluid leaks and the whine doesn't seem to be getting any worse BUT I've heard a couple different things. A friend of mine who used to be a Ford mechanic, told me that I could drive it as-is forever and probably not have any serious issues. Another friend who is also a respected mechanic, in my mind, told me I should get it taken care of sooner rather than later.


What do you all think? Should I be getting this taken care of ASAP or is this something I can afford to wait on?

My truck does the same thing, as of right now I'm not going to fix it and just turn the radio up a bit. When I do replace it though I'm going to put a LS like the Detroit Truetrac in it instead of rebuilding an open diff.

service it.. see what happens.. you never know what some fresh gear oil will do..

I've rebuilt rears for these trucks. The standard rears, not the LSD's. Honestly, it's a cake job so long as you have the right tools. But, we wouldn't just replace the pinion bearings. If one bearing is whining...chances are, debris has contaminated your fluid, and the differential bearings as well as the axle bearings should be replaced. It's about 2 hours worth of labor, and a full rebuild kit isn't terribly expensive. The price your were quoted seems very fair, but for a full rebuild, it might jack up a bit. Speaking from experience, do a full rebuild with all new bearings and seals. It's the right way to do it to insure you don't just fix one issue and develop future issues down the line.

I just did a fluid change: Royal Purple plus two bottles of friction modifier. Fixed the rear end chatter I was experiencing but the whine remains.

So you have the LSD. Servicing the rear won't really do much for a bearing whine. The races and/or rollers are worn. You're going to have to replace them to get rid of that sound.

I too have the "whine" at 50 mph. 2004. LS. Two years ago and about 20,000 miles I was told by a mechanic the rear end was shot. Beginning to think it isn't shot, just likes to make noise at a certain speed. I did the oil change back then, used royal and ford ls juice, gears etc. looked pristine. I am going to keep driving it. 96000 miles currently.

Had the rear end whine in my '07 that had gotten progressively worse. Took it in last week and got the call I was expecting...bad bearing at 77k miles. We'd purchased the extended warranty when we bought the truck a couple years back and we're only out $100. And with just about 6,000 miles left on the warranty. Lucked out this time.

What bearing? Axle? Pinion? Wheel bearing?

Checking out the service sheet and I see rear differential, pinion, and carrier.
Almost like the rear end was about to fall out of it. :eek: