New Silverado, 3.73 vs. 4.10 MPG and RPM

Nicky71 · July 11, 2002

Hope I'm in the right section for this question

Looking at buying a 2002 Silverado reg cab Z71 with the 5.3 (auto, of course). Currently focused on two near-identical trucks at a local dealer, but one has 3.73's and the other 4.10's. I would like some input as to the MPG difference and cruising RPM at 70 mph you all have experienced with these setups. Tires are 245/75/16.

Thanks for the help

CMNTMXR81 · July 11, 2002

What is your usage with this truck? That'll make a big difference in what gear you choose.

I can't compare 8.1L ext cab 4x4 2500HD with a 3.73 to mine with a 4.10 as mine came with 4.10's stock.

3.73 is a great "jack of all trades" gear. It offers the taller ratio of a 4.10, with some of the fuel economy of a 3.42. It'll work for most loads towed or hauled. For instance, most Silverado's, Tahoe's, Suburban's, etc, with 3.73's can pull up in the 7,000lb range easily. So unless you need maximum towing/acceleration, a 4.10 may not be necessary.

With my 8.1, ext cab, 6'.5" bed, 4x4 2500HD, I manage high 11's, low 12's on the highway for mileage.

See the thread by Gandolphxx (in this section I believe) about his switch from 3.73's to 4.10's and his feelings on it.

Shaners · July 11, 2002

If you are going to just drive the truck around and haul an occaisional load then the 3.73 gear is for you.

If you are going to work it hard and tow regularly or heavy loads then pick the 4.10's.

At 70 mph the difference in RPM's would be about 400-500 RPM more with the 4.10 gears. Mpg's shouldn't vary much between the 2 gear ratio by more than 1 mpg at the most (this is just a logical guess). I have heard stories of people getting better fuel economy with the 4.10 gears, but I can't substantiate it...

If you live in hilly terrain you will be happier with the 4.10 gears because the tranny won't shift as much. (Especially on the highway)

Jpshostr · July 11, 2002

With a truck like yours go 3.73. I highly doubt you'll be using this vehicle anywhere near where you'll need the advantages a 4.10 will give you, so may as well save a few RPMs and MPGs.

Now an HD pickup is different, IMO 4.10 is the way to go with these larger, heavier pickups that see hard use much more frequently.