Broken G80

IF YOU HAVE QUESTIONS ON THE REAR DRIVE SHAFT OR AXLE, IT GOES HERE.

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Broken G80

Post by photo_van »

Well my locker hasn't been working for sometime. Took a look in there today, everything looked ok, but there was a 1/2 long chunk of metal stuck to the magnet :yikes: I guess that might have something to do with it.
_MG_7833.jpg
Rebuild or replace; with what? Opinions?
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710
User avatar

mdmead
ASV Supporter
ASV Supporter
Posts: 2153
Joined: Sun Sep 10, 2006 6:45 pm
Location: Selah, WA
Been thanked: 1 time
Contact:

Re: Broken G80

Post by mdmead »

Custom 9" or Dana 60 with air locker. (Hey, it is easy for me to spend your money!) :muhaha:
Matt
Selah, WA
-96 GMC Safari AWD Hi-Top Conversion -->Stalled 5.3L swap & 5" lift
-74 Ford Bronco -->Far from perfect but mine!
-99 V-10 Ford Super Duty Super Cab 4x4 -->Stock with 285 Cooper ATs
-00 Ford Focus Wagon -->The Red Turd
-95 Ford 24' Class C Motorhome -->My big block sleeper
-07 Can-Am Outlander XT -->My yellow 4x4 quad for work & play
-04 Ski Doo REV Summit -->Still several chassis behind!


No new projects until the current ones are done!

ihatemybike
I plan to be buried in my van
Posts: 2224
Joined: Sun Jan 06, 2008 6:57 pm
Location: Elgin, IL

Re: Broken G80

Post by ihatemybike »

I bought Grumpy's G80 rear end from a scrap yard for $126.

Maybe give http://www.car-part.com a search.

I've recently acquired a low price source for new drivetrain parts.

Here's what I see available. I'll get prices.
Auburn Pro Series
Eaton Posi
Detroit Truetrac
Detroit Locker
Aaron

2005 Astro (Gandalf) - AWD, 4.3L, 3.42, 130k+ miles
1997 Astro (Grumpy - $250 Rally Van) - AWD, 4.3L, 3.42, LSD, 2" lift, 31" tires, 335k+ orig engine, $30 eBay fuel pump
Prev Astros:99,97,00,94,87,86

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Broken G80

Post by photo_van »

Are these G80 prone to failing compared to other lockers? Only 90,000 pretty easy miles on this one.
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710
User avatar

MountainManJoe
I have my van tatooed on my cheeks
Posts: 3088
Joined: Fri Aug 08, 2008 12:55 pm
Location: The Pacific North Wet
Has thanked: 44 times
Been thanked: 24 times

Re: Broken G80

Post by MountainManJoe »

They don't like being shock loaded.

ihatemybike
I plan to be buried in my van
Posts: 2224
Joined: Sun Jan 06, 2008 6:57 pm
Location: Elgin, IL

Re: Broken G80

Post by ihatemybike »

Searching the forums, I wasn't able to find many broken G80s. Broken 7.5/7.625 rear ends I was able to find several.

My normal cheap source for new drivetrain part quoted me higher than Summit Racing prices for LSDs and Lockers.
Aaron

2005 Astro (Gandalf) - AWD, 4.3L, 3.42, 130k+ miles
1997 Astro (Grumpy - $250 Rally Van) - AWD, 4.3L, 3.42, LSD, 2" lift, 31" tires, 335k+ orig engine, $30 eBay fuel pump
Prev Astros:99,97,00,94,87,86

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Broken G80

Post by photo_van »

Thanks for the link Aaron, that's a good one for me as the nearest salvage yards are three hours away!

Timeless; the shock loading is a problem, unfortunately at slow speed that's what happens, one wheel starts to spin and the other is stationary, that's a lot of static mass. There appears to be some "dainty" parts in the G80 and I'm wondering if any of the others are "beefier"?
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710
User avatar

1Gary
I have my van tatooed on my cheeks
Posts: 2743
Joined: Wed Oct 07, 2009 4:18 am

Re: Broken G80

Post by 1Gary »

Zam had Lifted put in a posi in his van.Might want to PM Zam about the details.
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY

LiftedAWDAstro
I have my van tatooed on my cheeks
Posts: 4379
Joined: Sat Sep 09, 2006 3:35 pm
Location: New Haven, NY

Re: Broken G80

Post by LiftedAWDAstro »

If you have the money, I feel the best posi is a Detroit True-trac. They require a complete setup as will any carrier you place in there. I installed a Power Trax no-slip locker in zam's van. It was an actual locker and not a posi.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy

Topic author
photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Broken G80

Post by photo_van »

Thanks Dean; I'm assuming the G80 is LS and not locking? I'm saving up to treat the old girl for her 100,000 mile anniversary. Thought she might like a low range and some 4:11's to make the second half of her life a bit easier. Might as well fix the locker while we're in there. It will be interesting to see what broke on the G80.
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710
User avatar

MountainManJoe
I have my van tatooed on my cheeks
Posts: 3088
Joined: Fri Aug 08, 2008 12:55 pm
Location: The Pacific North Wet
Has thanked: 44 times
Been thanked: 24 times

Re: Broken G80

Post by MountainManJoe »

It's kind of a hybrid. It does lock the axle for 50-50 power distribution but it behaves reactively.

LiftedAWDAstro
I have my van tatooed on my cheeks
Posts: 4379
Joined: Sat Sep 09, 2006 3:35 pm
Location: New Haven, NY

Re: Broken G80

Post by LiftedAWDAstro »

If you are swapping 4.11's in, you might as well save a little more for the True-Trac. The G80 is a locker but it operates in a finite speed range. The fly weights disengage it above about 30 mph.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy
User avatar

mdmead
ASV Supporter
ASV Supporter
Posts: 2153
Joined: Sun Sep 10, 2006 6:45 pm
Location: Selah, WA
Been thanked: 1 time
Contact:

Re: Broken G80

Post by mdmead »

photo_van wrote:Thanks Dean; I'm assuming the G80 is LS and not locking? I'm saving up to treat the old girl for her 100,000 mile anniversary. Thought she might like a low range and some 4:11's to make the second half of her life a bit easier. Might as well fix the locker while we're in there. It will be interesting to see what broke on the G80.
There was a discussion on the G80 several years ago and I thought the G80 was a limited slip. Dean posted up a video... proving me wrong! I'm not sure if this is the same video, but it gives a pretty good explanation. (The G80 is really a pretty impressive piece of work.)

[youtube]http://www.youtube.com/watch?v=tTGZOJQQBeE[/youtube]
Matt
Selah, WA
-96 GMC Safari AWD Hi-Top Conversion -->Stalled 5.3L swap & 5" lift
-74 Ford Bronco -->Far from perfect but mine!
-99 V-10 Ford Super Duty Super Cab 4x4 -->Stock with 285 Cooper ATs
-00 Ford Focus Wagon -->The Red Turd
-95 Ford 24' Class C Motorhome -->My big block sleeper
-07 Can-Am Outlander XT -->My yellow 4x4 quad for work & play
-04 Ski Doo REV Summit -->Still several chassis behind!


No new projects until the current ones are done!
User avatar

MountainManJoe
I have my van tatooed on my cheeks
Posts: 3088
Joined: Fri Aug 08, 2008 12:55 pm
Location: The Pacific North Wet
Has thanked: 44 times
Been thanked: 24 times

Re: Broken G80

Post by MountainManJoe »

photo_van wrote:I'm assuming the G80 is LS and not locking?
Forget terms such "limited slip", "locking", "positraction", "stability control" etc. Find out how stuff actually works! Every unit is different so putting it in a pigeon-hole is deceptive. You'll find that terms like bias, ratio, and distribution have more meaning than the marketing jargon.

Things that you need to know about the G80 are that it is reactive. In other words, one wheel needs to slip roughly 100RPM before you get any benefit. Torsen differentials are active so they are constantly adjusting torque distribution to keep you from slipping in the first place. The G80 has more or less two modes: open and 50/50 split, and as Lifted said, a narrow speed range that it can operate in. The Torsen, can never give you full 50/50 split and it is possible to get into a one wheel spin, but it works at all speeds and allows speed differentiation in turns. The Torsen also has far fewer parts and no clutches.

Cobra
ASV Supporter
ASV Supporter
Posts: 1750
Joined: Sat Jun 16, 2007 2:31 pm
Location: Toronto, Ontario
Has thanked: 1 time
Been thanked: 1 time

Re: Broken G80

Post by Cobra »

i think knowing the difference in a diff that locks the two axles together and one that allows one to rotate slightly faster then the other is important, so limited slip, locking and open do all have useful meanings. As far as i know all differential do one of those three things so if I understand anything about this G80 is that an accurate description would be a low speed reactive locker?
also i mentioned a long time ago that GM used the G80 code on many vehicles but from what i can tell all it means is there is some sort of traction aid in the rear axle (someone please correct me if i'm wrong) the Torsen (which i would put in the limited slip category) i just put in my 98 is the G80 for a camaro. There is another thread on here with more info on the Torsen and lots of good stuff on the net one of the reasons i picked it was the relatively simple design and no clutches to wear out.
1998 GMC Safari AWD, BFGoodrich AllTerrain T/A
Jet performance tuner 91 octane preset, Jet under-drive pulleys
Rancho 999000 series shock, on-board controller to be installed later
DHC rock rails and skid plate Add-A-Leaf
G3500 front calipers
Zexel Torsen Diff
11" drums
180 amp Alternator
Long tru-cool 4590 trans cooler

1997 gone
Post Reply