# noise from rear



## johnfin (Jun 9, 2013)

125K on gto and there is a hum at 40 mph especially when turning hard right. Noise is there with no load (ie foot off gas and coasting). Changed rear oil and made no difference. I was thinking a rear wheel bearing but those are radial load bearings so I would not think they would not make noise side to side. So.. that leaves the CV's, right?


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## GotTogO (Jul 25, 2013)

Maybe the side gears in the diff.


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## Lemans guy (Oct 14, 2014)

I second that emotion


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## johnfin (Jun 9, 2013)

Side gears? What exactly are you talking about? Do you mean case bearings or pinion gears?


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## GotTogO (Jul 25, 2013)

The side gears are in the differential on the posi unit.
You either rebuild the posi or replace it.
Now might be a good time to upgrade.

GForce might still have some spools left if you want
to get away from the posi.


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## svede1212 (Nov 1, 2005)

I'd lean more towards the wheel bearings. The diff has slop in the stubs and half shafts and I don't think there is much side loading with it on turns.


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## GotTogO (Jul 25, 2013)

I'm just sayin'.


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## svede1212 (Nov 1, 2005)

May be but it could also be the half shaft CVs. Diagnosing over the internet is fraught with guessing.


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## GotTogO (Jul 25, 2013)

Of course.

But the way he described it is very similar to my side gears going out.

Took forever to find it.


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## johnfin (Jun 9, 2013)

I have a subscription to ALLDATA and its pointing to the differential, noise on turns. The wheel bearings are radial loading, not side loading. Inside the carrier are tapered bearings, ie. side loading. Dealer wants $7K for the carrier and I am not sure I want some goober rebuilding my unit. What options and costs do I have?


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## GotTogO (Jul 25, 2013)

Aren't dealers great?

I'm probably not the best person to answer this, I'm sure others know more about it. But there is the TrueTrac and the Wavetrac. And GForce offers a 9" rear end (spendy though). There is also the spool which I mentioned earlier. This ties both axles together into one "semi" solid axle. It does away with the posi but can make tight and slow turns less smooth. I think the spool is the least expensive at about $350 for the unit. Followed by the TrueTrac, then the WaveTrac. I don't know what they're going for these days, you will have to look them up. You would also need new bearings ($100?) but you can reuse your current gear set (or upgrade). You could do the install yourself if you have a little know-how (rear end setup isn't hard, but it can be tricky and you need some special tools), or ask a local shop to do it (probably $600 to $1,000 in labor). 

Do some research, determine what best fits your needs, and find a good local shop and talk to them.


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## Qnko (Jun 8, 2014)

If you have to replace the diff go with truetrac. I have it on my car and am very happy with it. Wavetrac is twice the price. Don't do spool on the street. A friend of mine installed the truetrac and 3.90s for 300$. It was a package price though cause I brought him 2 transmissions and 2 rear ends, and it took him 3 months.


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## Saywhat (Nov 21, 2014)

Subscribed!


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