How do I determine which rear end gear is in my chevy trailblazer?

[David]

I'm looking to buy a used Chevy trailblazer. I know that Chevy used three different rear end gears in the trailblazers. Most of my driving will be around town, so I want the gear that will give me the best fuel mileage. How do I go about determining which rear end gear is in a particular trailblazer?

 

[REV B]

Open the glove box and look at the codes.
GU6- 3.42
GT4- 3.73
GT5-4.10
G80- locking rear diff

 

[REV B]

Open the glove box and look at the codes.
GU6- 3.42
GT4- 3.73
GT5-4.10
G80- locking rear diff

 

[buck b]

the 3.42 will get better becasue ur rpm will be lower at higher speeds

 

[buck b]

the 3.42 will get better becasue ur rpm will be lower at higher speeds