Kael

Have a 2005 Express 2500, chasing item #5 from PO. When in reverse, while rolling there is a slow high squeal, sounds in time with the propeller shaft. I read somewhere that it was probably the u-joints in the shaft and started replacement. After I removed the shaft from the diff yoke, I happened to rotate a tire (doing brakes too) and the squeal was still there, at the diff yoke. And only when it rotated counter clockwise (ie reverse). I listened close and watched, the sequence of the squeal is in line with the yoke, not the axle.

Thoughts? Seems fine driving forward, slow or at speed. I'm guessing pinion bearing needs replaced, but why a squeal? Shouldn't it grind, growl or something and all the time?

tech2

what about a brake backing plate contacting the rotor. I've had them make noise in reverse and be quiet forward. the sound would be a tinny scraping sound.

Kael

Nope, I've got the brakes off, including the parking brakes. And can tell the sound is right at the yoke from both sides.
Checking the diff fluid now, if I can get the damn fill plug out. It needs a square bit, sheesh.

mountainmanjoe

that's a square drive, like on ratchet.

Kael

3/8 is close, it's supposed to be a 10mm (3/8 is short .4 mm or so). I tried, scary part is it only goes into the plug about 1/8-3/16 and the plug is stuck. Fun fun fun.

Looked for a replacement, not seeing much, even from Rockauto. Surprised, these vans are all over the place, why are parts hard to find or require gold to get? Is the cargo van tax higher than the Corvette tax?!?

mountainmanjoe

I just use a 3/8 extension



fill plug should be same as drain plug right?

Kael

No, note that's listed for the front diff on an AWD. Might fit, hard to say. The one in my rear diff cover is more like a set screw, no head on it. Now that I look and consider 3/8, would say that one is too small.

mountainmanjoe

Oh I get it now. The plug comes with cover.
#88963585

Kael

Yeah, guess I'll have to get a new cover...to fill the diff...that the PO didn't.
I'm already shaking from the thought of removing the cover bolts.

Kael

Well, got the diff fluid changed, eventually. mountainmanjoe did me the favor of identifying the diff as a Dana 60 Super. Filled up to the plug hole today, while on the ground. And it still squeaks the same, like a baby carriage that needs a little oil. Forward is still fine, same as before.

Rats.
I'm hoping it's the oil seal, the squeak almost sounds like it's at the tip of the diff. But probably the pinion bearing is on its death bed. Hope it lasts until late summer.