4:11 vs 3:73

[LFD132]

How bad a drop in mpg can you expect with 4:10 gears vs 3:73?

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[Galaxie]

You thinking of a swap? Not horrible. Mathmaticly speaking its not a huge spread. Really, IMO not enough of a spread to do a swap. Totaly different bird but in a Mustang of mine I went from 3:08 to 3:55 to 3:73 to 4:10 back to 3:55 (over many years). Saw zero change from 3:73 to 4:10. Really was just changing for MPH and RPM and trap speed siturations.

My 7.3 had 4:10s and got over 20 MPG but it was a stick 4x2.

[skanj0]

Originally Posted by LFD132

How bad a drop in mpg can you expect with 4:10 gears vs 3:73?

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Depends upon tire size, and the % change from stock. If your new tires are 5% larger than stock, then you need about 5% change in gearing to return you to the factory "tire size/axle ratio", assuming that worked well for you.

From the photo in your post it looks like your truck has 37s. Assuming you plan to stick with that size (and weight) of tire, you might want to consider 4.56s.

[LFD132]

Another story, but I'm considering going back to a 6.0 and the truck I'm looking at is stock with 4:10 , gears. The biggest i would go with tires on it would be 35's.

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[snafu!]

IMHO 4.10s or 4.30s and 35s is the best combo.

[skanj0]

Originally Posted by snafu!

IMHO 4.10s or 4.30s and 35s is the best combo.

That's what I was thinking...

[JasonY]

4.10 should have been the stock gear and 4.30 for the trucks equipped with the 20" wheels with 34" tires.

I'd get the 4.10 truck.

Jason

[LFD132]

Truck was advertised as having 4:10 gears. After pulling an oasis it actually has 3:73's.

[g2shuck]

Love my 3.73 mileage

[Baddestt]

4.10s all the way, it will give you that rpm right in the sweet spot, a lil more bite on acceleration and pulling trailers without really sacrificing fuel mileage. Go 4.30s if you run 37" or larger tire or if you constantly pull heavy loads, go 4.30s.