rear end identification for a gmc sierra c2500 2wd 5.7 ltr

[thebannister8]

hi all...i have a 89 gmc sierra c2500 2wd and i'm trying to learn if the rear end is limited slip or something else...it has a 14 bolt cover plate and there's a casting on the side that reads cfo 9690...i don't see a tag on it and the information on the inside of my door is mainly missing...thanks

 

[Swaggerwagon]

the information about which axle you have will be on the RPO codes tag in your glove box

The gov-lock rear end code is G80

 

[thebannister8]

thanks for the reply...there are 2 stickers in the glove box...one is for camper information and the other is for parts identification...the parts identification one has alot numbers ( different codes )...what would the code be for non gov-lock rear end...how many kinds are there...and as a side question is there information anywhere for what all the codes mean...thanks

 

[dirtridinz71]

thanks for the reply...there are 2 stickers in the glove box...one is for camper information and the other is for parts identification...the parts identification one has alot numbers ( different codes )...what would the code be for non gov-lock rear end...how many kinds are there...

Here is a list of the rear end codes:
GQ1 -- AXLE REAR, STD RATIO
GT4 -- AXLE REAR, 3.73 RATIO
GT5 -- AXLE REAR, 4.10 RATIO
GU4 -- AXLE REAR, 3.08 RATIO
GU5 -- AXLE REAR, 3.23 RATIO
GU6 -- AXLE REAR, 3.42 RATIO
G80 -- AXLE REAR, LIMITED SLIP (POSITRACTION)

If it is an open rear end (no traction aids) then it will just list the gear ratio code. Is your truck a 6 bolt wheel pattern or 8? If 6 then you have a 9.5" semi-floating 14 bolt rear axle.

and as a side question is there information anywhere for what all the codes mean...thanks

http://www.rpocodes.com/

 

[thebannister8]

thank you for the information...i appreciate it

 

[81shkenbk90]

What does STD Ration mean?

 

[Tempted]

Probably something in the 2.70s.

 

[DRAGGIN95]

Probably something in the 2.70s.

Yeah 2.73, but not very many had it, thankfully!

 

[Tempted]

Yeah it was fine back when the 'Glides, TH350s and 400s were ruling the roost but when the auto ODs came along it was brutal on the highways.

 

[81shkenbk90]

Well my 90 k2500 has a GQ1 GT4 G80 on the RPO tag, I would post a pic if I knew how to ha