Help identify posi - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Speedracer39** · 11-23-2019, 01:37 PM

I just pulled this from my 72 c10 and was wondering if anyone can identify what brand it is ?

sweetk30 · 11-23-2019, 01:49 PM

rpo code - g80 = gov-loc . 10 and 12 bolt rear versions are kind of weak . the 14ff rear version much better .

if you know there there and how they work there fine . but for people beating on them and or hard / soft surface mix each tire and hit gas they can go BOOM / aka gov-bom nickname.

its a open diff until the 1 wheel spins faster than the specific rpm difference and then the fly weight swings in and locks the clutches up .

**Speedracer39** · 11-23-2019, 01:54 PM

Thanks for the quick response, Glad I did a gear and Truetrac swap.

**mongocanfly** · 11-23-2019, 02:42 PM

I thought govlock started in 73....right or wrong?

You did good with trutrac...

**truckster** · 11-23-2019, 05:13 PM

Quote:

Originally Posted by mongocanfly

I thought govlock started in 73....right or wrong?

You did good with trutrac...

I'm not sure what year they started, but my 72 had one that was original... until it exploded through the pumpkin.

**mongocanfly** · 11-23-2019, 05:30 PM

Ok..thanks....I thought I read somewhere that it came about in 73

Bigdav160 · 11-23-2019, 08:09 PM

Quote:

Originally Posted by truckster

I'm not sure what year they started, but my 72 had one that was original... until it exploded through the pumpkin.

Really? My '72 had a clutch based spicer unit. On the spid too.

edit: not the truck in my sig. That has a gov loc know (14 bolt)

**PGSigns** · 11-23-2019, 08:27 PM

They did come out in 73. So it may have been transplanted some time in the trucks 48 years of mods.
Gov-lock is GM's name for the differential. G80 is the RPO code used by GM to identify the option. Its was introduced by GM in the newly redesigned 1973 trucks as the G86 option, an upgrade from the G80 which was a clutch type limited slip also known as Positraction.
Jimmy

**truckster** · 11-23-2019, 09:52 PM

I guess I can't say for sure. I didn't get it until 2007, so anything is possible. It was definitely the factory 12-bolt housing, though.

I never knew a differential could come apart in so many pieces. It was fragmented like a grenade.

11-23-2019, 01:37 PM	#1
Speedracer39 Senior Member Join Date: Sep 2016 Location: Omaha Nebraska Posts: 589	Help identify posi I just pulled this from my 72 c10 and was wondering if anyone can identify what brand it is ? Attached Images

11-23-2019, 01:49 PM	#2
sweetk30 Registered User Join Date: May 2012 Location: horseheads,ny rust belt Posts: 2,794	Re: Help identify posi rpo code - g80 = gov-loc . 10 and 12 bolt rear versions are kind of weak . the 14ff rear version much better . if you know there there and how they work there fine . but for people beating on them and or hard / soft surface mix each tire and hit gas they can go BOOM / aka gov-bom nickname. its a open diff until the 1 wheel spins faster than the specific rpm difference and then the fly weight swings in and locks the clutches up . __________________ 77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great.

11-23-2019, 01:54 PM	#3
Speedracer39 Senior Member Join Date: Sep 2016 Location: Omaha Nebraska Posts: 589	Re: Help identify posi Thanks for the quick response, Glad I did a gear and Truetrac swap.

11-23-2019, 02:42 PM	#4
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,583	Re: Help identify posi I thought govlock started in 73....right or wrong? You did good with trutrac... __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

11-23-2019, 05:30 PM	#6
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,583	Re: Help identify posi Ok..thanks....I thought I read somewhere that it came about in 73 __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

11-23-2019, 08:27 PM	#8
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: Help identify posi They did come out in 73. So it may have been transplanted some time in the trucks 48 years of mods. Gov-lock is GM's name for the differential. G80 is the RPO code used by GM to identify the option. Its was introduced by GM in the newly redesigned 1973 trucks as the G86 option, an upgrade from the G80 which was a clutch type limited slip also known as Positraction. Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

11-23-2019, 09:52 PM	#9
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,794	Re: Help identify posi I guess I can't say for sure. I didn't get it until 2007, so anything is possible. It was definitely the factory 12-bolt housing, though. I never knew a differential could come apart in so many pieces. It was fragmented like a grenade. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.