Ok, firstly... i hate asking this type of question. But, ive found that the collextive brainpower, and experience hrs in here... usually just rolls with my dumbness.

I noticed this morning that i had a grinding high pitched repetitive squeal/squeak under the truck. Could hear it until i got fast enough for wind noise to drown it out. This afternoon i had the wife sit in the truck in Low while i walked beside. Forwards, and in reverse, same thing. Coming from the rear. I just changed wheels, and the brakes looked fine, also, braking does not change the tone, or the timing. I used my super scientific squeak diagnosis elixer (wd40) on the drive shafr in front of the rear diff, on the rotoes, and all the lug nuts on the rear axle. As well as the parking brake cables. None of that changed a thing. Had to deive 2 hrs to okc with a load of firewood tonight. Did that. On arrival, the intermittent. Has become constant. Now. Im wondering if my shot parking brakes could be the source? In which case ill be annoyed, until i get time to swap them out, but no biggie, really. My concern, and the reason im posting is, could there be any other, particularly any badness type things that could also be making that noise, so i can maybe check, a d save myself some headache later on?

 

Carrier bearing?

or

If you have a cardan joint, check that. Mine was squealing before it failed and for the life of me I could not find the source until it was replaced after u joint failure...and the squeal was gone

 

You changed the wheels, are you sure you don't have a riding condition due to that?

 

I will have to crawl under and look, to see if i have one...

Im not 100% sure that i dont, but theh are weld racing wheels, and went on easily, with no apparent abnormal contact points. I went from stocl 16, to these 18s, so of anything, i should have greater clearance.

 

If it started right after the wheel change my guess is that one of the brake shields, the thin sheet metal things, got bent and is rubbing the rotor. If it wasn't related to the wheels I say driveshaft carrier bearing, which was my first thought 'till I considered the new wheels.

 

Can the noise be reproduced by jacking up the rear end and turning each hub by hand?

 

The 'Parking Brakes' and the 'Stopping' brakes on the back hubs use two different brake pad systems. There is a pad system for stopping and a pad system for the parking brake. Pull the back hubs off (if you can???? may be very hard to do) On my back wheels, one was 'fine' and one was dragging badly. see if you have one 'parking brake' dragging. back the parking brake off a little.

(I do not use my parking brake any more) my MPG also went up because my parking brake is not dragging any more.

 

Jacking up the back end. Thats on my to do list, soon as im able.
My parking brakes are totally shot. Wont hold a thing. Thats why i wonder if on is just riding in there

 

You may have 'ground down' your hub where the parking brake engages on one or both of the hubs. One of my back parking brake area on the hub (metal) looked almost brand new... the other had more than half ground off and in very bad shape. Did not 'make noise', but did 'stick' and drag.... backed off both and put back together. 'Parking Brake' did not seem to work anyway, so I knew not to rely on it.

 

The parking brakes have a two piece actuator that freezes up and causes the parking brakes to not work. It would also cause them to not fully release if you use them. I believe that that is a large cause of bad parking brakes.

 

have to take apart and lube, or what would the approach be to checking that out?

 

The mechanism is accessible once you take the disc brake rotor off. Simply remove the brake rotor and look at the top side of your parking brake assembly. You will see the mechanism clearly, and the parking brake cable leading up to it from the other side of the dust shield.

 

imo take hubs off, inspect parking brake parts, use brake cleaner on all parts, lube silicone spray, (not on pads) moving parts

 

These links found in the 7.3L PSD Tech Folder should give you a better visualization of what you are looking at/for.

• E-Brake R&R
• E-Brake Shoe R&R With Hub On

EDIT: I HATE PHOTOBUCKET!!! Those images were not like that when IDI-Charlie was nice enough to take them for us. Perhaps @IDI-Charlie can rehost them here on the FTE and I can help him edit the write-up if needed.

 

For a quick check you could have someone else work the parking brake whilst you stick your nose down in behind the backing plate. The parking brake cable ends at the actuator and as they work the parking brake you should be able to see it move.