SOLVED! 97x 8.6 LSD Is my Rear End Toast?

TequilaWarrior

Well-Known Member
Edited to replace incorrect information (thanks @HARDTRAILZ) .
Does it say g80 or g86 on the rear diff cover? Bc mine SAYS g86 but is definitely an 8in bc it uses that gasket.
Update: After 2 weeks of driving the pinion seal and gasket are not leaking amazingly. I had used the old gasket and seal (big no no but had wrong parts). Will be pulling apart in 3 weeks to update and change these out
Replying to you directly so you get a notification.
G80 is not the RPO code for 8.0 inch. G80 is the RPO code for a locking diff - regardless of ring gear size.
G86 is not the RPO code for 8.6 inch. G86 is the RPO code for limited slip - regardless of ring gear size.

You having a G86 in 8.0 inch is 100% a valid factory configuration. It's limited slip in an 8.0 inch differential.
Me having a G80 in 8.0 inch is 100% a valid factory configuration. It's a locker in an 8.0 inch differential.
The same can be said for these two RPO codes even if the vehicle has an 8.6 inch differential - which were the rear end for all V8s, except for SS and Aero which were Corp 14 bolt 9.5 with G86 (limited slip).
 
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HARDTRAILZ

Moderator
Sweet. great pics and documentation. Nice info to finally have!

The SS and Aero only have a 9.5 14 bolt and G86.

The other V8 had the 8.6, as did all the LWB versions.
 

Maverick6587

Silver Supporter
The SS and Aero only have a 9.5 14 bolt and G86.
Do you know if they were limited slip? I assume they were, since they were both AWD. I assume 4WD or 2WD were not an option for the SS and Aero?
 

HARDTRAILZ

Moderator
They were the G86 limited slip. Our platform did not have the g80 locker available in the 9.5. I had to swap in an open carrier and lunchbox locker for my needs.

They have a different transfer case as well for their awd. No 2wd or 4wd or high or low selections available.
 

HARDTRAILZ

Moderator
I have no need for a TC without low range so never paid attention.
 

Mooseman

Moderator
The Torsen was only in the SS and Aero and was the only full-time AWD TC. The other AWD trucks (Bravada, 9-7x, Rainier) got the NP 126 non-selectable part-time TC. It engages the front wheels only when rear wheel slip is detected. It's basically the same as setting the NP 226 to the A4WD setting.

I think it can all be summarized as follows:

4.2L non-AWD truck:
SWB: 8.0 diff, either a G80 locker or open diff, NP 226 TC (if 4x4)
LWB: 8.6 diff, either a G80 locker or open diff, NP 226 TC (if 4x4)

4.2L AWD truck:
8.0 diff, G86 LS or G80 locker diff, NP 126 TC

5.3L non-AWD truck:
8.6 diff, either a G80 locker or open diff, NP 226 TC (if 4x4)

5.3L AWD truck:
8.6 diff, G86 LS diff, NP 126 TC

6.0L truck (SS and Aero)
9.5 diff, G86 LS diff, Torsen TC (if AWD)
 
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OP
OP
Pygot

Pygot

Silver Supporter
I would like to see the G86 on the cover.

The gasket has nothing to do with G80/G86/or fully open. The gasket is affected by the ring and pinion size, not the slip options.
I was referring to the 8.6 seen below, which according to other posts does not really give much insight :/
 

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TollKeeper

Well-Known Member
The Torsen was only in the SS and Aero and was the only full-time AWD TC. The other AWD trucks (Bravada, 9-7x, Rainier) got the NP 126 non-selectable part-time TC. It engages the front wheels only when rear wheel slip is detected. It's basically the same as setting the NP 226 to the A4WD setting.

I think it can all be summarized as follows:

4.2L non-AWD truck:
8.0 diff, either a G80 locker or open diff, NP 226 TC (if 4x4)

4.2L AWD truck:
8.0 diff, G86 LS diff, NP 126 TC

5.3L non-AWD truck:
8.6 diff, either a G80 locker or open diff, NP 226 TC (if 4x4)

5.3L AWD truck:
8.6 diff, G86 LS diff, NP 126 TC

6.0L truck (SS and Aero)
9.5 diff, G86 LS diff, Torsen TC (if AWD)
Isnt there also a...
4.2L non-AWD truck EXT Wheelbase:
8.6 diff, either a G80 locker or open diff, NP 226 TC (if 4x4)
 

Blckshdw

Moderator
Isnt there also a...
4.2L non-AWD truck EXT Wheelbase:
8.6 diff, either a G80 locker or open diff, NP 226 TC (if 4x4)
Sounds like mine... 2WD, and no locker, so I always assumed it was open.
 

Sparky

Moderator
The 8.6 axle I put in my 02 was originally from an ext, not sure which engine. Yes it was open (dumb JY gave me the wrong thing but w/e).

Just a note, the 8.0 and 8.6 both on this platform use the same pumpkin gasket. You can actually stick the deeper 8.6 cover on an 8.0. The innards of the 8.6 are the same as every other GM 8.6 axle but the pumpkin is NOT. So the gasket is absolutely not an indicator at all what axle you have.
 

Maverick6587

Silver Supporter
Maybe only the limited slip 8 inch differentials have the odd shaped gasket then?
 

Sparky

Moderator
Both my open 8.0 and my open 8.6 replacement in my TB used the black rubber gasket earlier in the thread.

The 8.6 in my Silverado uses the blue one. I just used RTV when I changed its oil as what was on there was not reusable when I opened it.
 

Mooseman

Moderator
Thanks for the summary - that's a good idea.
My Bravada (AWD) has the 8.0 diff, but it's definitely a G80 full locker from the factory.
Corrected. I think the main thing to remember is that the 4.2L SWB always got the 8.0. LWB and 5.3L always got the 8.6 (also added that info).

I was referring to the 8.6 seen below, which according to other posts does not really give much insight :/
That definitely says 8.6.
The 8.6 axle I put in my 02 was originally from an ext, not sure which engine. Yes it was open (dumb JY gave me the wrong thing but w/e).

Just a note, the 8.0 and 8.6 both on this platform use the same pumpkin gasket. You can actually stick the deeper 8.6 cover on an 8.0. The innards of the 8.6 are the same as every other GM 8.6 axle but the pumpkin is NOT. So the gasket is absolutely not an indicator at all what axle you have.
So are the pumpkins of the 8.0 and 8.6 G80 the same? Would it be possible to replace the 8.0 G80 ring and pinion with a 8.6 G80 and the R&P along with the cover? I have a G80 8.0 and have seen a new 8.6 G80 carrier for sale. All I would need is a 8.6 R&P set (and would go to a 3.73 or 4.10 instead of the 3.42 I have now)
 

Sparky

Moderator
So are the pumpkins of the 8.0 and 8.6 G80 the same? Would it be possible to replace the 8.0 G80 ring and pinion with a 8.6 G80 and the R&P along with the cover? I have a G80 8.0 and have seen a new 8.6 G80 carrier for sale. All I would need is a 8.6 R&P set (and would go to a 3.73 or 4.10 instead of the 3.42 I have now)
No, the 8.6 pumpkin is a little deeper. It also has an extra gusset.

Also if you bolt an 8.0 cover on an 8.6 it will line up but you'll tear a hole in it first rotation. I want to say someone here did that before by accident when doing a swap or replacing a rusted 8.6 cover.
 

Mooseman

Moderator
So I'd have to source an '06+ EXT or V8 diff. Most of the trucks are older and I have yet to see a V8 at all in the u-pull yards.
 

Sparky

Moderator
The EXT was canned a couple years before the whole platform IIRC so that makes them even harder to find.
 

Mooseman

Moderator
Yup. Saw one in a yard once but it was away from home (Was hunting parts for the Caprice at the time). Did snag the brake caliper brackets from it. Also saw an EXT LT in person. Practically a unicorn.
A rare sighting: '06 TB EXT LT
 

Reprise

Lifetime VIP Supporter
Gee, if I ever decided to sell mine, I know where to post the ad for MAXIMUM response... :laugh:
 

northcreek

Well-Known Member
While we're talking rear ends, I saw this gem on CL . I think somebody was looking for one awhile ago.
00s0s_5wvYUbAWt9a_600x450.jpg
ps seller says it's an AXEL so it does jumps on ice skates too....
 
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HARDTRAILZ

Moderator
Seems like a fair price on the SS rear. Without mileage known though, it is a crap shoot
 

TollKeeper

Well-Known Member
I would rock it.... If I didnt have to get a my drive shaft shortened.... And it wasnt so far away!
 

northcreek

Well-Known Member
Seems like a fair price on the SS rear. Without mileage known though, it is a crap shoot
Seems almost too nice to be from a rust belt area(Erie Pa.). It's either low miles or came from a dry climate state. Lots of extras on there to make it a good deal for someone...:dance:
 

Mooseman

Moderator
Could have been stored winters, which is the case with a lot of sports type vehicles and collectibles.
 

northcreek

Well-Known Member
Could have been stored winters, which is the case with a lot of sports type vehicles and collectibles.
Or possibly wrapped around a pole before it's first birthday...:cry:
 
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Sparky

Moderator
Yup. I have a car like that, 21 years old and no rust because it was never exposed to that salt.
 

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