Offroad Trailblazers and Envoys

Swapping a G80 into an open rear-end

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by boog2006 » Wed Jul 31, 2013 2:42 pm

Project: Pull a G80 from a GT4 8.0" rear-end at the local u-pull-it; Install into my GU6 open rear-end
Cost: $35 for carrier

Let's start this buy saying I've never even pulled a cover on a differential before. :facepalm:

I've read JD's write-up on rebuilding the G80. Removal of the existing unit seems straight forward.

My question is this, what issues am I going to run into installing it? Do I need to be sure and get certain parts of the donor vehicle?

Thanks,

Boog
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by Trail X » Wed Jul 31, 2013 5:28 pm

It's actually Donny's writeup.

And honestly, if you've never pulled a differential cover before, it would make infinitely more sense to grab the entire axle.

Swapping a carrier requires shimming the carrier.
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by boog2006 » Wed Jul 31, 2013 7:35 pm

Hmmm...what if I have someone who's setup rearends before helping?
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by The Roadie » Thu Aug 01, 2013 9:29 am

If they have experience and guarantee their work and will do it for cheap beer, you might save money. Most of us just slap in a junkyard axle.
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by bartonmd » Thu Aug 01, 2013 10:19 am

My uncle swapped a G80 out of an 8.6 into the 8.6 in his truck, and the shims were the same as stock for his rear end. Tolerances are so good on OEM stuff any more, so they don't have to adjust anything at the factory, that if you take an OEM carrier out of the same model and year range of axle and put it in yours, it shouldn't require different shims than your carrier did in your axle. Depending on the ratio, yours could have different shims than the one you took it out of, but if you use your shims in your axle with any OEM carrier that came out of another like-model, like-year vehicle, it SHOULD be the same. Always want to do a pattern check just to be safe, though.

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by boog2006 » Thu Aug 01, 2013 10:33 am

bartonmd wrote:My uncle swapped a G80 out of an 8.6 into the 8.6 in his truck, and the shims were the same as stock for his rear end. Tolerances are so good on OEM stuff any more, so they don't have to adjust anything at the factory, that if you take an OEM carrier out of the same model and year range of axle and put it in yours, it shouldn't require different shims than your carrier did in your axle. Depending on the ratio, yours could have different shims than the one you took it out of, but if you use your shims in your axle with any OEM carrier that came out of another like-model, like-year vehicle, it SHOULD be the same. Always want to do a pattern check just to be safe, though.

Mike


Great info! Thanks!

I think I'm going for it...Now i just have to find time to get over there since they're only open M-F, 8-5 :wallbash:
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by boog2006 » Thu Aug 01, 2013 5:24 pm

Pulled the donor G80 today...now to decide if I want to try putting it in before another Turkey Bay run on Saturday.
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by RyansTBLS » Thu Aug 01, 2013 5:36 pm

We want pictures, when you do. :lurk:
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by boog2006 » Thu Aug 01, 2013 8:47 pm

ImageUploadedByTapatalk1375404415.420160.jpg


In my truck now...
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by ErikSS » Fri Aug 02, 2013 1:17 pm

How do you like it? Any noises?
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by navigator » Fri Aug 02, 2013 1:38 pm

I think he meant inside of his truck not installed.
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by boog2006 » Fri Aug 02, 2013 2:19 pm

Correct...I don't think I'll be able to install it tonight before the ride tomorrow...hopefully install next week. I still need to pick up new oil, torque wrenches, and gear compound to check the pattern. I may also have to get a buddies impact. I had to use an impact to remove the 3.73 ring gear.
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by Moots1288 » Fri Aug 02, 2013 3:18 pm

boog2006 wrote:Correct...I don't think I'll be able to install it tonight before the ride tomorrow...hopefully install next week. I still need to pick up new oil, torque wrenches, and gear compound to check the pattern. I may also have to get a buddies impact. I had to use an impact to remove the 3.73 ring gear.
ImageUploadedByTapatalk1375467567.417899.jpg
the impact definitely makes it alot easier. Cannot wait to see we done. Good luck
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by HARDTRAILZ » Mon Aug 05, 2013 9:11 am

Just take your time and hopefully your friend has the experience to teach you.
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by fishsticks » Fri Aug 09, 2013 1:41 am

My gear swap thread has pictures of a good pattern.
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by boog2006 » Mon Feb 24, 2014 2:36 pm

So, this took along time to complete. And, I'm sorry to say I ended up paying to have it done. But my local mechanic did a great job. He inspected everything and ended up pressing on new bearings and completely refreshed this. I don't have my reciept on all that was done in front of me, but I'll post up a final cost for the swap.

I did test this out at the farm yesterday in some knee deep mud to make sure everything was working well. :flex dirty: Looking forward to trying some of the trails I've gotten hung up on in the past to see the difference.
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