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2002 chevy trailblazer_ltz
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Discussion Starter #1
Can you install a G80 locker in a rear differential that doesn't have one without getting a whole new rear end? I'm a bit of a noob when it comes to the actual mechanics of it...
 

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yes you can buy a G80 locker. The issue is installation requires a skill set that most of us do not have. So in most cases its simply far easier, and alot of the time cheaper to just get a whole axle used with a g80 in it.
 

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Yeah you can get just a G80 installed in your TB a competent axle shop can do it in maybe a day or in 1/2 a day or so. Like a shop here in Vegas called Dave's Driveline deals only with axles and well driveline parts and they quoted me before about 300-400 for everything to install one in my TB.
 

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Discussion Starter #4 (Edited)
G80

Would it be cheaper/easier to install to just find a used G80 axle at a junkyard or something and have a shop swap them out?
 

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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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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.
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.
 

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Yeah you can get just a G80 installed in your TB a competent axle shop can do it in maybe a day or in 1/2 a day or so. Like a shop here in Vegas called Dave's Driveline deals only with axles and well driveline parts and they quoted me before about 300-400 for everything to install one in my TB.
I have assumed that the axle housing for the G80 with the 8.5" ring gear is larger than the housing for the 8.0 inch ring-geared open differential. Am I mistaken? 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. I was going to scrap everything, but if they are the same, then...:undecided
 

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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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What I sold was the carrier with the ring gear attached, and the pinion gear. I guess I have always used "pumpkin" to refer to the carrier with the ring gear attached. I've also referred to it as the "center section". Perhaps I've been mis-using those terms all my life. Too soon old, too late smart.

I didn't know there was a G80 for the 8.0" gear. I thought that to get the G80 you had to move up to the 8.6" differential. Now I know. Thanks.

So, I have the housing for the 8.0" diff, the axles and the calipers and brackets. Any reason to save them, or should I scrap them? If somebody wanted to pick them up, they could have them for free!
 

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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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Thanks for the info roadie! I've searched for awhile to get a difinite answer. Does the 97x also have the 8.6"? There is a 3.73 unit close to me with 15k for 400 bucks. My reason for upgrading to the 8.6 is the choices for the posi unit. I know some have had good luck with the gov lock... but I'm not a fan. The 8.5 gov lock in my S10 only lasted 15k before giving up.
 

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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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I have assumed that the axle housing for the G80 with the 8.5" ring gear is larger than the housing for the 8.0 inch ring-geared open differential. Am I mistaken? 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. I was going to scrap everything, but if they are the same, then...:undecided
Yes they are the exact same thing whether open or posi so no worries :)
 

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All great info, but what if a guy wants to go trolling the auto recyclers for a G80-equipped rear axle. 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? On my last three cars the build sheet was on the underside of the trunk lid; where is it on hte trailvoy? Oh, and are the ring&pinion sets the same ratio on all non-ss models?
 

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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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