Think I have a worn ring and pinion...

[doncaruana]

Earlier this year I noticed that I could hear this whining sound that got a bit louder with speed. Can't hear it until maybe 30mph and then it gets louder. At freeway speed it is constant, but if I hit the gas, it will change a little. That's the only thing that changes the sound other than the speed. I even got off the freeway and put it in neutral and coasted and the sound did the exact same as it does normally.

It's coming from the back and I *think* it's a worn ring and pinion. This is a 97 Tahoe with 235K on it. I've not had any issues with the drive train at all. But not really being a car guy at all, I'm not sure how much to worry about this. I can't repair it myself and it will probably cost a grand to repair (right?).

From reading here, it seems like this is one of those things that can be fine - and then tip over suddenly. I drive 60+ miles of freeway daily with this truck. Get it into the shop ASAP? Or does it sound like something that I should take off my worry list and get to it whenever?

 

[drakon543]

Just off hand since you haven't mentioned it have you checked the fluid in the front and rear diff along with the transfer case? Simply being low on fluid can cause it to be a little noisy. If your pretty confident its coming from the rear end and its not low on fluid remove the cover to get the old gear oil out. Go to a local parts store or i think even walmart might have it but get some 95w and refill it with a new cover gasket. I think factory they only have 75 or 80w in them and with 230k it might have thinned out by now. Using 95w might quiet it back down, if it does leave it alone until it starts making noise again.

 

[Yukon John]

Change the fluid front and rear and add some Lucas Gear Oil Treatment to it.

 

[1998Suburban]

Pull the rear diff cover & have a look around, specifically for metal. Bad carrier bearings whine all the time, excess runout in the ring gear tends to howl between coast & drive (no gas & a lot of gas). There's a guy who did a how to rebuild the rear end in his Astro van with 200K+ miles and, with no gear oil changes, the bearings looked nasty. I'll have to see if I can find it.

 

[1998Suburban]

Found it.
http://www.astrosafari.com/viewtopic.php?f=108&t=4572