G80 Question

[nickygn23]

I hope somebody could help me out. Heres the question. Did all grand Nationals all come with posi-rear(G80)? I've seen some that say on the service parts sticker some say G87. (peg-leg rear) I beleive. I'm monster fan of GN's soon will have one in the garage. Don't want to make a mistake.
Thanks

 

[TR Custom Parts]

Not all came with posi. If it doesn't say G80 on the trunk tag it didn't come from the factory with posi. However, over the years it is possible someone did put a posi unit in. Jack up the rear of the car where both wheels are in the air. Put the car in neutral and try spinning one wheel by hand. If the other wheel turns in the same direction it has a posi unit installed.

 

[mikestertwo]

G80= Positraction
G87= 8.5 in Rear

 

[87GNSteve]

I hope somebody could help me out. Heres the question. Did all grand Nationals all come with posi-rear(G80)? I've seen some that say on the service parts sticker some say G87. (peg-leg rear) I beleive. I'm monster fan of GN's soon will have one in the garage. Don't want to make a mistake.
Thanks

Its really more important to buy the rest of the car in good condition, don't pass up a car without posi for one in rough shape with posi. You can add posi for around $500.

 

[streetknight]

However, over the years it is possible someone did put a posi unit in. Jack up the rear of the car where both wheels are in the air. Put the car in neutral and try spinning one wheel by hand. If the other wheel turns in the same direction it has a posi unit installed.

Not always the case. My buddies GN has an Auburn in it and they spin opposite ways when jacked up in the air, but both pull in the burn out box.

 

[incubus2432]

Its really more important to buy the rest of the car in good condition, don't pass up a car without posi for one in rough shape with posi. You can add posi for around $500.

I agree completely. My GN was a factory peg-leg but for less than $500 and a few hours in the garage problem solved.

 

[MENTL231]

My brother in law's 86 GN. Came without a posi. Its funny because its got every other option available. Astro roof. Digital dash. Etc. and no posi. =)

 

[1fast6]

G80 rear's are not posi. They are a locker type rear. They will not always spin together when rear tires are off the ground so that is not a good way to tell.


[youtube]tTGZOJQQBeE[/youtube]

 

[TurboDave]

G80 rear's are not posi. They are a locker type rear. They will not always spin together when rear tires are off the ground so that is not a good way to tell.


[YOUTUBE]tTGZOJQQBeE[/YOUTUBE]

No, they're not posi, but rather more accurately, "limited slip". However, the example you're showing is an Eaton unit. The G80 G bodies did not come from the factory with eaton units. The factory G80's will spin in the same direction when off the ground.

 

[1fast6]

unless there different, my 88 k5 has a g80 and it is an Eaton set up. I thought all g80 were. I have not been into a gn rear so maybe I should'nt speculate.

 

[NorEaster]

Posi

No, they're not posi, but rather more accurately, "limited slip". However, the example you're showing is an Eaton unit. The G80 G bodies did not come from the factory with eaton units. The factory G80's will spin in the same direction when off the ground.

Positive Traction (what Chevrolet and Buick called it), Posi for shot, is the correct term if you have a G80 option code. Posi has been generalized for a LSD (Limited Slip differential). Other companys called their LSD other names, GM trucks in the 80s had Gov-Lock, Chrysler had Sure Grip, AM's had twin grips.

Kinda like ordering a coke.

 

[1fast6]

GM trucks in the 80s had Gov-Lock, Chrysler had Sure Grip, AM's had twin grips.

Kinda like ordering a coke.

So, is the gov-lock in my 88 k5 different than the g80 in my 87 gn?

 

[Black3]

So, is the gov-lock in my 88 k5 different than the g80 in my 87 gn?

GM uses the G80 code for both limited slips (cars) and locking diffs (trucks) even though the 2 units have totally different mechanics and characteristics.

 

[1fast6]

thanks for info

 

[nickygn23]

Thanks a lot. I appreciate it .

 

[nickygn23]

Thank you. I appreciate it.

 

[haywire4130]

GM uses the G80 code for both limited slips (cars) and locking diffs (trucks) even though the 2 units have totally different mechanics and characteristics.

right on tr's come with a spring-loaded clutch-type posi, trucks came with the "gov-loc" (functions as an open diff until the wheel speed differs enough that the governor locks up violently, thats why the wheels spin opposite when you jack it up as mentioned above. in park, if you spin one wheel briskly, the governor will swing out and the wheels will slam to a stop), both were option code g-80. the gov loc wouldn't stand a chance in a tr, they weren't designed for burnouts or any other abuse, i've replaced a few of them that scattered catastrophically! for example, if one wheel would be on ice spinning and the other tire was on dry pavement, when it locks up, it would grenade the carrier. $$$