Rear Axle Identification

vonclod

vonclod

Greasemonkey
Nov 19, 2012
182
16
Delta B.C.
martin.ca said:
Ideally...



But on mine, I found it easier to look up the RPO codes from the VIN via the big book behind the GM parts counter. And it had been already changed in the past.
thanx man much appreciated
 
P

possigrandprix

n00b
May 28, 2013
4
0
I also gave a 8.5 gn rearend and I am having trouble identifying the axle tube code. It is 9tp g 091. If anyone could help I would appreciate it thanks.
 
stevec8337

stevec8337

Greasemonkey
Nov 24, 2012
101
18
im currently running a 7.5 with 4:10 gears posi trac in my Malibu out of a 1982 el camino that originally had posi 2:41 gears. if anyone is wondering about it being dependable my motor is pushing over 450hp to a worked th350 and I haven't had any issues with the rear end. when I pulled mine out the junkyard it had a metal stamp on it saying posi fluid only and a code stamped on it but I would have to go look at the car for the code.
 
firebuick

firebuick

Not-quite-so-new-guy
Oct 7, 2014
6
1
montreal quebec canada
here you can see both side by side notice the 7.5 the cover is not round like the 8.5

the only mode you need to do is to cut 1 inches from youre driveshaft brake , drums ,is all the same


 
axld86

axld86

Greasemonkey
does anybody have a backing plate to backing plate measurement for our factory 7.5/7.625" ? reason I ask is the 9'' G-body I ordered from a rear end shop has my wheels /rim VERY close to my frame rails, and I sold my original one before I thought to measure it.
 
axld86

axld86

Greasemonkey
does anybody have a backing plate to backing plate measurement for our 7.5/7.625'' rear ends? reason I ask is I installed a G body 9" and my wheel/rim are VERY close to my frame rails and I sold my original before I thought to measure it.
 
Rktpwrd

Rktpwrd

Royal Smart Person
Feb 2, 2015
2,090
113
Calgary, Alberta, Canada
Hey fellas, resurrecting an old thread here.
Through a very lucky set of circumstances, I stumbled on an '85 442 in the wrecking yard here. Naturally, I first determined that it was indeed the 8.5" 10 bolt, and mostly confirmed that it had the 3:73 gears (about 80% sure). I checked the RPO code on the underside of the trunklid, and it did NOT have the G80 (posi) option. Seeing that it's definitely stronger and better geared than my 2:56's, I snapped it up today anyways.
:)
Now that it's out and safely at home soon to go in, I tried researching the axle code stamped on the front of the passenger side tube. Unfortunately, nothing I've found on any of the common sites corresponds to what my stamping actually is.
Can anyone definitively decode and identify what my axel code is?
image.jpeg

In case it's not clear in the photo, it reads:
8TF G 007
Thanks in advance for any help anyone can provide on this.
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
24,816
113
Kitchener, Ontario
I would remove the cover to check the gear ratio and if it's a posi. Who knows what has been done to the rear end after all these decades and I'd want to change the oil anyway
 
  • Agree
Reactions: Rktpwrd
Rktpwrd

Rktpwrd

Royal Smart Person
Feb 2, 2015
2,090
113
Calgary, Alberta, Canada
I would remove the cover to check the gear ratio and if it's a posi. Who knows what has been done to the rear end after all these decades and I'd want to change the oil anyway
The cover will definitely be removed and repaired/replaced as the auto wreckers I got it from punches a hole in the bottom of the cover to drain the oil before it hits the yard.
With no oil in it, fresh lube is mandatory.
All the research I've done so far points to most if not all 442 rears in '85 as having 3:73 gears. I've already confirmed its not a posi, but I found that the axle code being different than what's listed online as strange. Still hoping someone can shed some light on what this code breaks down as or meant originally. Anyone?
 
O

oldsmobile joe

G-Body Guru
Nov 12, 2015
993
93
mpls
from my '85 service manual, 3.73 gears, open carrier.
IMAG0807.jpg
 

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