GM Rear Axle Advice - Yukon Gear?

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My Envoy is equipped with a GM 8.0" 10-bolt rear axle and a 3.73 (RPO GT4) ratio. Lately, I've started noticing some faint whining/howling at highway speeds, which goes away if you cut the throttle/disengage cruise control, so I'm going to have it professionally rebuilt.

While I'm going to stick with the factory 3.73 ratio, I'm looking at a helical limited slip differential, such as the Torsen T-2 I have in both my Fords. Torsen does not make one for this application, but Eaton has the Detroit TrueTrac 912A654.

I'm also looking at Yukon Gear for the ring and pinion gear. It is about $100 more than Genuine GM, and many seem to swear by it, but is it really any better? Wondering if anyone in the know has suggestions or recommendations before I start buying parts.
 
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Faint gear whine, I would leave it alone. That differential probably would outlast the vehicle. May be just a wheel bearing which isn't a big deal to repair. A professional diagnosis should be done before going too extreme on this. I recently had a whiney rear end, ended up being a loose pinion nut. I retorqued it, setting the preload to specs and the noise is virtually gone which is good for me.
 
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I would not pay $100 more for Yukon than OE unless there is some sort of known problem with the OE...

So it goes away on decel, how about throttle?
 

Falcon_LS

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Faint gear whine, I would leave it alone. That differential probably would outlast the vehicle. May be just a wheel bearing which isn't a big deal to repair. A professional diagnosis should be done before going too extreme on this. I recently had a whiney rear end, ended up being a loose pinion nut. I retorqued it, setting the preload to specs and the noise is virtually gone which is good for me.
I certainly did have it looked at, and was told it was coming from the ring and pinion. The unit's always been serviced regularly, the bearings are good, there are no leaks and I'm certain this will not cause me any problems at all, but it does bother me enough to take action.

Still haven't fully decided where I'll be going with this, but since I'm also looking to rebuild and twin turbo charge, it is something I want addressed along with the transmission. There's always the option of going with something like a 10.5" 14-bolt, but that's overkill since the stock axle is good for up to 900 hp. So I reckon this is a good time to be getting this rebuilt along with a helical LSD.

I would not pay $100 more for Yukon than OE unless there is some sort of known problem with the OE...

So it goes away on decel, how about throttle?
That is what I was thinking. No known issues with the factory gears, at least from all my research. I think my issue was running the grape juice scented 75W-90, while most people with almost 3 times my mileage have zero problems with their differentials running 75W-140. This is the only vehicle I've run 75W-90 in, and ironically the only one with the whine...even though it's not too noticeable.

I would buy a louder stereo.
Guess my 6,000 watt all-Pioneer setup with two subwoofers is pretty mediocre.
 
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Gear whine is a common issue in late model GTO's, a lot of guys use Torco RGO to quiet the whine. While not a complete fix it helps I used it mine until I put a tru trac in it. Its expensive fluid but not as expensive as new gears and posi unit. Since you have a slight whine it may help.
 
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I have Yukon gears in my YJ (5.13s) and Grizzy lockers (also made by Yukon) front and rear and have been very happy with their products.

I am not certain if their gears are stronger than OEM -- I just read you're planning on some pretty significant power. I wouldn't have guessed a 10 bolt is good for 900 hp...but I'm thinking from an off-road application perspective, where I'm confident they aren't.

You didn't ask, but if you're building for big power, I'd compare costs between a 12 or 14 bolt and doing the rebuild of your 10 bolt. Might be worth the peace of mind (plus no risk of having to do it all over again).
 

Falcon_LS

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Gear whine is a common issue in late model GTO's, a lot of guys use Torco RGO to quiet the whine. While not a complete fix it helps I used it mine until I put a tru trac in it. Its expensive fluid but not as expensive as new gears and posi unit. Since you have a slight whine it may help.
Thank you! That might be a decent short term solution, although in the grand scheme of things I will need to do something about the rear end before moving on with the project.

I have Yukon gears in my YJ (5.13s) and Grizzy lockers (also made by Yukon) front and rear and have been very happy with their products.

I am not certain if their gears are stronger than OEM -- I just read you're planning on some pretty significant power. I wouldn't have guessed a 10 bolt is good for 900 hp...but I'm thinking from an off-road application perspective, where I'm confident they aren't.

You didn't ask, but if you're building for big power, I'd compare costs between a 12 or 14 bolt and doing the rebuild of your 10 bolt. Might be worth the peace of mind (plus no risk of having to do it all over again).
Thank you for the heads up! I just wasn't sure if they were in anyway "superior" to OE that's manufactured by American Axle Manufacturing.

A cost comparison is definitely worth doing, however, for long term peace of mind. (y)
 
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Get the AAM gear as they're cheaper. I highly doubt a 8" diff will handle serious power......A 8.6" isn't even good above 700 foot pounds in a heavy vehicle with drag radials.
The Trailblazer SS came with a 9.5" 14 bolt & that's where I would start with your power goals.
 

Falcon_LS

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Get the AAM gear as they're cheaper. I highly doubt a 8" diff will handle serious power......A 8.6" isn't even good above 700 foot pounds in a heavy vehicle with drag radials.
The Trailblazer SS came with a 9.5" 14 bolt & that's where I would start with your power goals.
That is awesome! Thank you very much, Clinebarger!
 
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I had a read end whine that several mechanics whonheard it said pinion bearing.

The needle bearings in u joint were diagonal and flat. No noticeable slop in u joint.
 
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On the Jeep forums, Yukon seems to be a mixed bag--some love them and others state they are junk. I am about to re-gear my Rubicon and I chose Dana Spicer (the OEM) versus Yukon. The other thing to consider about Yukon (at least for the Dana 44 Advantek in the Jeep) is they are substantially more expensive and I am not sure that you are gaining anything for the increased cost.
 
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<----- I have Yukon gears in my trail Jeep and am using them on my buggy build.

Yukon (and Optima Batteries) sponsors my friend's buggy in the King of the Hammers race. I don't believe he's ever had a diff issue.
I also like Dana Spicer, so economics will likely play a role in your choice for a stock application.

Regarding the rebuild - I would have the diff diagnosed before dropping the coin to rebuild. It could be a number of things that may be more easily repaired and keep more beer money in your pocket.
 
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