biglee88

I have a 03 superduty on 37 inch mud grapplers. I have the factory 3.73 gears in it. I want to regear the axles to help my Trans out on the highway and regain some power I've lost. I wanted to go to 4.88 gears, but my friend works at a salvage yard and can get me low mileage axles with 4.30 gears. so I'm debating on doing the 4.30 I know it'll help but will my truck still be gutless? It only has the 5.4 I tow pretty often but nothing super heavy maybe 5000 pounds.

Twisty

I'd go 4.30.
4.88's are REALLY low.
You only have 37 inch tires. If you were running 42's or bigger you'd want 4.88's.

biglee88

I know it but it would pull with 4.88

biglee88

I know it but it would pull with the 4.88

Twisty

You need to calculate your engine rpm's at cruising speeds with different gear sets.
You will get up to speed quickly but your top speed at peak efficiency will be lower.
I'm getting a truck that has 4.30's. I don't drive over 65 and I slow down on hills when towing.
Have fun!

Z7What

With 37" I'd go 4.88s


I ran 37" with 4.56s and wish I had the little extra.

Wayne

biglee88

We'll when I tow its never over 50 and I slow down on hills let the Trans get in 2nd and run it up to around 2 and she'll pull almost anything even on 37,s 4.30 will be closest to stock but im wondering if I should do lower just for more umph and if ill notice the any large difference between the gears