posi rearend

i believe the G80 option is posi and the G87 option was open differential. it was how it was optioned and there are/were G87 options on the Grand National
 
Ok thanks haven't seen the rpo sticker yet just hopeing it has the g80 code on it. I would hat to have 1 wheel peel on a gn
 
G87 stands for the 8.5" differential. Either G80 will be there or not determining if factory posi install.
 
All my hotairs (5) had non posi diffs. I had to install posi in 2 of them (1GN and 1 T Type). Others I left open diff. My 87 already had factory posi installed. Much better driving in my opinion.
 
yes 87 late production of Gns (sept 1 1987 - dec 11 1987) the g80(posi) was made standard with the gn package (we2), and they raised the base price accordingly.

for all before that it was an option and 86 seems to have more open rears than 87
my 86 was open

open rear cars also received aluminum rear drums , posi would have steel (except for the gnx)

open rear cars will also be missing the lower body bushing in the #7 postion (by the rear bumper)
posi cars will have that bushing
 
yes 87 late production of Gns (sept 1 1987 - dec 11 1987) the g80(posi) was made standard with the gn package (we2), and they raised the base price accordingly.

for all before that it was an option and 86 seems to have more open rears than 87
my 86 was open

open rear cars also received aluminum rear drums , posi would have steel (except for the gnx)

open rear cars will also be missing the lower body bushing in the #7 postion (by the rear bumper)
posi cars will have that bushing
So interesting.. wonder if the reason to forego #7 in peg legs was to help with weight distribution over the wheels?
 
I may be wrong, but I thought it was standard G80 AXLE POSITRACTION LIMTIMED – SLIP DIFFERENTIAL on the RPO, unless it came with the aluminum rear brake drums. I guess they thought over at Buick, that if you had the Aluminum rear brake option, you don't need traction...LOL
 
Good info is timeless.. the 1st 10 years of the archives has more of it than the last
 
My 87 WE4 did not have posi from the factory, and aluminum brake drums. One of the first mods I made, along with a K&N, and test pipe. And of course, a chip..........
 
yes 87 late production of Gns (sept 1 1987 - dec 11 1987) the g80(posi) was made standard with the gn package (we2), and they raised the base price accordingly.

for all before that it was an option and 86 seems to have more open rears than 87
my 86 was open

open rear cars also received aluminum rear drums , posi would have steel (except for the gnx)

open rear cars will also be missing the lower body bushing in the #7 postion (by the rear bumper)
posi cars will have that bushing

So interesting.. wonder if the reason to forego #7 in peg legs was to help with weight distribution over the wheels?

first two items from pacecarta's post => yes. in '86, G80 option was $80.75 or $95 on the sticker depending car model and production date.

last two items re: open rear cars....this is not something I have looked into.
 
My 87 gn didn’t come posi best way to tell if it’s low mile like mine was the non posi had aluminum rear drums … first mod was Eaton rear diff an more spline axles
 
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