Grear ratio for a 1998 GMC Sierra

[KentuckyRifle]

I am thinking about buying a 1998 GMC Sierra C/K1500 4x4 Extended Cab with a 6.5 engine from a dealership over the internet. They have been pretty helpful but one thing they cannot tell me is what the gear ratio is. After doing some reading on here I know that 3.42 is what I want, as fuel savings are my number 1 goal in buying this vehicle. (Currently I drive a 1997 Dodge RAM 1500)

Since this is a lighter truck it makes sense to me that most of them would have been made with the 3.42, but I have no way of verifying this. Was there a standard gear ratio for those trucks? I would appreciate any info. Thanks!

[joed]

The two 1500's I've seen had 3.73s, so hard to say.

They should be able to look up the RPO code on the sticker inside the glovebox.

GT4 = 3.73
GU6 = 3.42
G80 = Locking rear diff.

Hope that helps.

Joe.

[KentuckyRifle]

Thanks for the help.

Would the general consensus be that I should still get significantly better mileage with the Sierra than I am currently getting with my Dodge RAM?

[Hubert]

It depends on the condition of the truck and HOW YOU DRIVE. You'll get a little variation of MPG calculations depending on how patient you are filling tank to exact same fill.

FYI I get 16-18.5 MPG depending on driving and fuel additive etc etc.

Lots more to maintenance and cost of operation than saving on mpg unless you drive the wheels off. Make sure you understand that after 100K miles some relatively expensive maintenance is looming for long term ownership. Lots of people think Diesels run forever and are better high milage engines. This can be kind of true but $$$ maintenance is required.