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Differential Whine

T

tjcdmc

Full Member
Joined
Jul 26, 2002
Messages
18
I have an 02, Z66 with a 4:10 diff. that whines at 45 mph but only if I let off the gas. Has anyone else experienced this?
 
My Z71 does this also, but not all the time. Seems to be worse when cold.
 
Do a search on this topic...i remember someone having a bad set of rear gears and got them replaced or something...it was awhile ago....

HTH
 
Do you have the Locking Rear Differential? I do but have not experienced excessive noise from it on my Avalanche. ?However, GM makes a differential additive (GM additive 1052358 ) that they often put in the posi-track differentials of Corvettes to quiet them down. ?I used two tubes of it in the locker differential of my Cobra and it made all the difference in the world (It's great stuff!). Check with your dealer and see if they recommend using the additive for your Avalanche.
Okiesnake
 
I assume it whines above 45 too? If it's a whining noise coming from the rear only when you let off the gas, it's a bearing in the rear diff going bad on you. The gears are probably fine. (If it happens when you're on the gas too, then maybe it's a wheel but that doesn't sound like your problem.)

My '95 Silverado (which will hopefully be replaced by an Avalanche in the near future) has this problem... but it has 155K on it. I had to have someone ride along with me because it was difficult to tell exactly where it was coming from with only one person. My mechanic rebuilt the gears in my rear diff not too long before this but the *insert creative word here* guy didn't swap out the bearings while he had the whole thing apart. I won't be going back to him.

You should be under warranty though. I'd recommend you take it in, tell 'em you think that's what's wrong and see what they say.
 
TJ,

I've been having the same problem. I also own a Z66 with 4500 miles. However I have the 3.73 instead of the 4.10 axle ratio. I also have the locking diff.

The whining only occurs when I'm over 40mph and I take my foot of the gas. The noise will stop with the slightest pressure on the gas pedal. Weird!

I'm not sure what's up,........and visions of the dealer ripping apart my rear axle just doesn't sit well with me.

Anybody have any suggestions to calm my worries.

J
 
jguzek said:
TJ,

I've been having the same problem. ?I also own a Z66 with 4500 miles. ?However I have the 3.73 instead of the 4.10 axle ratio. ?I also have the locking diff.

The whining only occurs when I'm over 40mph and I take my foot of the gas. ?The noise will stop with the slightest pressure on the gas pedal. ?Weird!

I'm not sure what's up,........and visions of the dealer ripping apart my rear axle just doesn't sit well with me.

Anybody have any suggestions to calm my worries.

J
Click to expand...

I'll bet you a $5 fan club sticker that it's a bearing in the rear diff. That's exactly what you're describing. The whole darn thing pretty well has to come apart. Sorry. :cautious:
 
Mine has done it since day one...

Above 45, under 65 or so. 4.10 gears.. Eaton mechanical locker...

I believe the additive mentioned will only work on clutch pack posi's... ours are a mechanical flywheel with a set of gears and a ramp.. :( Eaton G80

My understanding on the whine is that is's caused by the way the gears are set up. I remember reading about how to set up a new set of gears, if you're installing them yourself. If they whine off the gas, it's such and such adjustent... On the gas, it's this... etc. etc.

I'm personally not going to worry about it.. it hasn't got any louder, and is barely noticeable in itself.
 
Got a similar problem but my whine is at certain rpm (1900)...and speed is 45 and 63 mph. Anyone else have this problem???
 
I had this problem after only having 200 miles on my Ava. Brought it to the dealer and they replaced the ring and pinion gears. Haven't had a problem with the noise coming from the rear since. I do still notice a whine though when I put it in 4-wheel drive :rolleyes:
 
I too had a Z66 3.73 with the whine, gas off, 50-60mph. Took it to the dealer...tech took all of 3 seconds to diagnose bad ring and pinion gears. They replaced them and the noise was gone. However, there was a noise at 55-60 that was similiar only with the gas ON. It went off with the gas off. Just when I was going to take it back in I found a big leak in the midgate and talked them into giving me another AV. This one too has the noise at 55-60 with the gas ON. I saw another post of a guy who seemed to think the rear differential wasn't setup or aligned right and that caused the ring and pinion gears to 'float' at those speeds. He was taking it in to have it adjusted. He seemed to know what he was talking about. Mine is going in next week.
Not sure if his was Posi or not. That seemed to be an issue with that set of posts. Hope this helps. ???
 
I mis-spoke in my earlier post. I stated the whine occurs when I'm off the gas. That was incorrect.


The whine actually occurs when I'm applying very little gas and the engine is at 1500 to 2200 rpms. (the whine may continue at higher Rpms but the engine noise covers it up.)
I can hear it very well when I'm coasting at speeds from 40 to 60mph and I apply some gas. Once you let off the gas,....the whine stops.

I have a Z66, 3.73axle, 4500 miles
 
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