Gear Ratio Question

[JRLZ71]

Ok, I've looked and looked and maybe I'm just that stupid, but I can't figure out what my gear ratio on my truck is. It's a 2008 Gmc Sierra ec 5.3 v8 z71

[MS3DALE]

Look in your glove box at the SPID label.

GT4 is 3.73

GT5 is 4.10

GU6 is 3.42

G80 is the locking differential

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It's either 3.42 or 3.73, probably 3.73. Look in glove box and there should be a code on the GM parts identification sticker that starts off gt and then a number. Post the g codes and I'll look at them and see what you got.

[JRLZ71]

GT4...

 

Would there be any significant difference if I re-geared to 4.10?

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It's either 3.42 or 3.73, probably 3.73. Look in glove box and there should be a code on the GM parts identification sticker that starts off gt and then a number. Post the g codes and I'll look at them and see what you got.

 

D*mnit, as soon as I posted, I realized that Rich beat me to it!

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GT4...

 

Would there be any significant difference if I re-geared to 4.10?

 

I don't know why you'd want to. You'd have to change the rear and front diff. gears. correct speedometer error. less gas mileage on hwy. Better quarter mile times and more torque are all side-effects of lower gears!

[MS3DALE]

It's either 3.42 or 3.73, probably 3.73. Look in glove box and there should be a code on the GM parts identification sticker that starts off gt and then a number. Post the g codes and I'll look at them and see what you got.

 

D*mnit, as soon as I posted, I realized that Rich beat me to it!

 

 

Sorry

[pm26]

What is the code for the 4.56 ratio gears? I know you cannot get those on 1/2 ton pickups, but 1 ton cab and chassis trucks are still available with that gear ratio I think.

[MS3DALE]

I'm going to have to look Pete,I know its not available in anything anymore,even 1-ton chassis-cabs.

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What is the code for the 4.56 ratio gears? I know you cannot get those on 1/2 ton pickups, but 1 ton cab and chassis trucks are still available with that gear ratio I think.

 

I want to say G82, but Rich will back that up when he gets done "looking it up".

[MS3DALE]

What is the code for the 4.56 ratio gears? I know you cannot get those on 1/2 ton pickups, but 1 ton cab and chassis trucks are still available with that gear ratio I think.

 

I want to say G82, but Rich will back that up when he gets done "looking it up".

 

 

Nope,4.56 is RPO code HC4

 

G82 isn't a good RPO code at all.

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What is the code for the 4.56 ratio gears? I know you cannot get those on 1/2 ton pickups, but 1 ton cab and chassis trucks are still available with that gear ratio I think.

 

I want to say G82, but Rich will back that up when he gets done "looking it up".

 

 

Nope,4.56 is RPO code HC4

 

G82 isn't a good RPO code at all.

 

 

Ok, G82 is an old code for 4.56 gears, It's in my old 71 Cheyenne 1ton truck. Hc4 is more recent. I can't believe I was wrong at something.

[MS3DALE]

What is the code for the 4.56 ratio gears? I know you cannot get those on 1/2 ton pickups, but 1 ton cab and chassis trucks are still available with that gear ratio I think.

 

I want to say G82, but Rich will back that up when he gets done "looking it up".

 

 

Nope,4.56 is RPO code HC4

 

G82 isn't a good RPO code at all.

 

 

Ok, G82 is an old code for 4.56 gears, It's in my old 71 Cheyenne 1ton truck. Hc4 is more recent. I can't believe I was wrong at something.

 

 

Well a lot of the RPO codes like that stay the same year after year,so I can see why you thought G82 was it,Obviously that one changed over the years.

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When I looked up the codes for my 2005, 2500HD CC it said:

G80 =Differential, Zexel-torsen, limited-slip, rear

 

Are all year G80's the Zexel-Torsen mechanical posi units? If so, they are not "lockers" in the usual sense of the term - ie Detroit Locker (Yes/No?)

 

- - -EDIT

Hummmm... Just looked it up on http://www.compnine.com/

and it states "G80 - Available 1976 to 2009

AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80)"

 

Bummer.... looks like the G80 is in fact, the Eaton aka Detroit Locker style...

 

Wonder where I found that first RPO look-up site?

[hockeypro1411]

When I looked up the codes for my 2005, 2500HD CC it said:

G80 =Differential, Zexel-torsen, limited-slip, rear

 

Are all year G80's the Zexel-Torsen mechanical posi units? If so, they are not "lockers" in the usual sense of the term - ie Detroit Locker (Yes/No?)

 

- - -EDIT

Hummmm... Just looked it up on http://www.compnine.com/

and it states "G80 - Available 1976 to 2009

AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80)"

 

Bummer.... looks like the G80 is in fact, the Eaton aka Detroit Locker style...

 

Wonder where I found that first RPO look-up site?

 

The RPO "G80" is limited slip in cars. In the trucks it's a mechanical locker. The same RPO codes can mean different things depending on the application.