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I have a 2008 1500 with a 3:42 w/G80, anti drum brakes.  I want to go to 3:73 rears. The diff had the spacer break and cause case and bearing damage. I changed the bearing and re shimmed. I want to replace the entire axle with an 3:73 ratio. I was wonder what years models will be an direct swap. Will some earlier years work??

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Why posted in the Hybrids, Xtra Fuel Economy, and AFM special section?

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2 hours ago, Drastic396 said:

I have a 2008 1500 with a 3:42 w/G80, anti drum brakes.  I want to go to 3:73 rears. The diff had the spacer break and cause case and bearing damage. I changed the bearing and re shimmed. I want to replace the entire axle with an 3:73 ratio. I was wonder what years models will be an direct swap. Will some earlier years work??

Spacer?  Is your Sierra an XFE model?  If so, it originally came with 3.08 gears and someone didn't want to properly upgrade the carrier to run 3.42s so they used the adapter/spacer.  Stick with GMT900 pickups if you want a complete rear axle.  Now, is your axle an 8.6" or 9.5"(10-bolt or 14-bolt)?  I suspect the former.

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It came with 3:42. I’m going to 3:73 to help in pulling my camper. 8.6” 

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On 7/30/2019 at 2:11 PM, Drastic396 said:

It came with 3:42. I’m going to 3:73 to help in pulling my camper. 8.6” 

I missed this response.  So the RPO sheet has code GU6 and you have a spacer on your carrier to run a 3.42 gear?  Does not sound original to me.  Would have to see pictures if important enough at this point.  A properly sized carrier would be strongest.

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    • By Drastic396
      I have a 2008 1500 with a 3:42 w/G80, anti drum brakes.  I want to go to 3:73 rears. The diff had the spacer break and cause case and bearing damage. I changed the bearing and re shimmed. I want to replace the entire axle with an 3:73 ratio. I was wonder what years models will be an direct swap. Will some earlier years work??
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