Does anyone know if there is an RPO code specific to the 9 bolt differential? I know that if you crawl under the car and look at the actual axle, you will see one of the following numbers, which means the corresponding gears are inside.



1985
10032243 3.08 Std
10032244 3.08 Posi
10032245 3.27 Std
10032246 3.27 Posi
10032248 3.45 Posi
10032250 3.70 Posi
10032268 3.08 Posi
10032270 3.27 Posi
10032272 3.45 Posi
10032274 3.70 Posi
14085324 3.42 Std
14085325 3.42 Std
14085326 3.75 Std
14085327 3.73 Std

1986
10032270 3.27 Posi
10032272 3.45 Posi
10032274 3.70 Posi
10040660 2.77 Posi

1987
4ET 2.77 Posi
4EW 3.45 Posi

1988-89
4EW 3.45 Posi
4EU 3.27 Posi
4ET 2.77 Posi



However, is there a code (other than WS6 and and just inferring from what it entails) that specifically means your car came with a nine bolt?

Thanks
-Corrupted

G80 or G92

RPO codes for the MOSTcommon 9-bolt ratios:
GH3=2:77
GW6=3:27
GM3=3:45

okay, so i guess that means that there is no code that will tell me if there is a nine bolt, ten bolt, twelve bolt, fourteen bolt, or whatever the case may be. Just codes for what's inside. you have to tell what ratios go with what axles.

[QUOTE]Originally posted by SaintedCorrupt
okay, so i guess that means that there is no code that will tell me if there is a nine bolt, ten bolt, twelve bolt, fourteen bolt, or whatever the case may be. Just codes for what's inside. you have to tell what ratios go with what axles. [/QUOTE

Those are the codes fot 9-bolts ONLY. Other RPO will tell if its a 10-bolt. the Axle codes you listed are Worthless.

I was under my car tonite using a mirror to try and get my axle codes for my 9 bolt (dont try this) The only numbers i could figure out were 0578 then i think the next ones were either 05620 or 02650 but i cant figure it out could someone list the axle codes for a 9 bolt 1989 T/A? I need to know if I have a 2.77 or a 3.07 hopefuly the 3.07. Thank You!

mine had a little aluminum tab attached to one of the cover bolts that had the ratio printed directly on it. the guy who owned the car before me was pretty **** about keeping with GM parts. any little problem (fuses included) and it was back to the dealership, so it could be a dealer thing.

If you have a factory stock 350 and the rear has not been changed, you will in MOST cases have a 9-bolt 2:77 (Note: a 3:27 was optional). No such rear as a 3:07.
Again the stamped numbers on the axle housing are next to worthless in try to identify the gear ratios. Check the RPO numbers (if you have them) or just pull the cover and check the Stamped numbers on the ring gear for correct ID.

Yes G80 means a 9 bolt.

I thought G80 meant LSD?

Edited:

Actually took a look at my '89 Helms, G80 is "axle, rear locking type. Limited slip"

RPO's for '89 (via Helms)

GH3-2.77
GM3 3.45
GU2 2.73
GU4 3.08
GU6 3.42
GW6 3.27


So what DJP posted was correct, since the 2.77,3.45 and 3.27 Are BW ratios...

G80 only indicates LSD. I think that's a standard RPO through the GM production line of RWD cars.

Mine has 0578 029010 BW BY 3-45D stamped on the ring gear. I counted them and it came out to be 38 and 11 which is 3.45s.

For starter the stamped code numbers on the Housing are only Mfg data for the Housing. And if you have a TA with a 350 the axle ratio most common was a 2:77. The other is NOT a 9- Bolt ratio. Check your RPO Codes for the ratio ID and to a search for there meaning.