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Banned
2004 gmc
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26,181 Posts
I did precisely that, and upgraded to the stronger EXT rear axle at the same time for only $430 and a half day's work for two people.
 

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Banned
2004 gmc
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26,181 Posts
Is the axle housing the same, whether you have an open diff or the G80? I ask because I have an axle housing from my 2003 Envoy that had an open diff--I sold the pumpkin but still have the housing and axles and calipers and mounts.
What did you sell? Maybe the carrier? The "pumpkin" is a nickname for the housing usually, or the entire diff.

The housing is different only if you have the larger ring gear. So an open carrier can be replaced by a G80, as long as you get the right one. An 8.0" diff needs an 8.0" G80 (GM # 12479123), and the 8.6" diff needs an 8.6" G80 (GM #12471529)

I have a few questions about this. First, I've seen some online 4wd stores list the 8.0 and 8.5/8.6 rear ends for the 02 and up TBs. So am I correct in assuming the SWB I6 have the 8.0 and only the LWB V8 have the 8.5/8.6? And second, did you reuse your stock brakes or did you change them as well? TIA.
SWB I6 is 8.0" ring gear, yes. SWB V8, offered in later years than yours, is 8.6". ALL EXT/XL/XUV models have the 8.6" diff, both I6 and V8.

SWB SS uses a 9.5" 14-bolt rear end with a limited slip, not a locker, which is why a swap to an SS rear end was never an attractive option, although there are more choices of true lockers for the 14-bolt. They also come with 4.10 standard gears, so any rear upgrade would also have to involve the front diff gears as well. Or jump them both to 4.56, as AlekG did.

I reused by original calipers on the new axle. Plug and play. Just chose the best set of rotors, since the recycled axle came with rotors.
 

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Banned
2004 gmc
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26,181 Posts
I didn't know there was a G80 for the 8.0" gear.
I did four years of ever-more-difficult trails including the eastern third of the Rubicon, with an 8.0" G80. Teebes still hasn't upgraded his rear axle to EXT, but he and I do the most extreme western stuff the trucks can handle.
 

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Banned
2004 gmc
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26,181 Posts
Saabs offered all three engines, but I've never found an on-line parts database to understand what was in their rear ends. Sorry. They all came with AWD, so no NP226 transfer case with the LO range. Without a LO range, they're not as interesting to me. ;)
 

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Banned
2004 gmc
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26,181 Posts
Aside from looking at the build sheet for the G80 RPO code, or removing the diff cover and seeing what's inside, are there any other cues to look for?
Try it functionally. It's the only other way. If one rear tire is in the air, just spin it quickly. Only 100 RPM will set off the locker. Typically, with a fast spin, within 1/4-1/2 turn, it will lock up and stop because the other tire is on the ground.
On my last three cars the build sheet was on the underside of the trunk lid; where is it on hte trailvoy?
Inside the glovebox door.
Oh, and are the ring&pinion sets the same ratio on all non-ss models?
There are three ratios. The RPO codes for them have been posted a few dozen times, and are in the RPO code lists under the "resources" pull duwn menu.
 
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