My 02 QC is lifted on 35's with 3:92 gears (4.7L automatic) and I'm averaging 11.5 m/g city and hwy combined. What are you guys getting out there? I'm wondering if I shoul look into a set of 4:10's


p.s. I'm fairly new to the forum, what is the avatar and how should I have it set? Thanks.

 

<=my avitar is my trucks

I noticed you posted a pic of your truck, you can resize that and set it as your avitar. just go into my profile and go from there

anyway, for a new vehicle that sounds about right, it should get a little better once thins get broken in.

I've got a spreadsheet somewhere that can tell one the revs that are produced with different gearings and such. realy, if you put 4.10's in it would prolly put your speedo right where it needs to be and also give you a bit more pep from the engine since your getting a little bit more mechanical advantage running taller gears.

with my Cummins, 6 speed, and 4.10's I get around 18 city and highway

 

Thanks for the reply,

I do know that my speedo is off almost exactly 5mph at 65-70 highway speeds, I checked it recently with a handheld GPS on a trip I took from my current home town (Orange County, CA) to my soon to be home town (Tucson, AZ).

p.s. Let's see if my avitar worked this time.

 

I didn't think there was a big differance between 3:92 and 4:10

 

Apparently it's enough for a 5 mph difference at highway speeds. I'm also thinking that because my speedo is off obviously my odometer is off and that 11.5 p/g is probably not the correct milage the truck is getting. I theory the truck is traveling 5 more miles an hour at 65 mph than my odometer is recording. So I think my milage is probably slightly better than the 11.5, but how much better? If I don't get the gears I might look into an ECU programer (Hypertech, Jet, etc.) I now you can adjust your odometer along with shift point, air/fuel, etc. with them.