Quick question on differential gears with a Powerstroke.

I have to make a decision by Monday on two trucks. Nearly identical 2001 Powerstroke, automatic transmission, crewcab trucks.

Both are lifted with 35" tires.

One with 3.73's, one with 4.10's. It is snowing here, so I spun the tires on both anytime I stepped on it hard.

Mostly highway miles planned with some towing of a CJ-5.

Which gearset do I want for overall use?

Either will be chipped at some point, but not much else in the way of modifications.

Fuel economy is a concern.

No flames please, just want some quick feedback. Wasn't planning to buy the truck so quickly, but they have the car my wife wants also, so we are going to try and swing a two car trade in and purchase by Monday.

Thanks,

Mike

I have a 02 with stock tires and 3.73 so I would have to say with 35s you should get the 4.10.

Agreed. Running the 35's I would go for the 4.10's.

I have a '96with a gear vendors overdrive unit and 4.10. My overall final ratio is 2.49 running 32" tires, nets me 1650 rpms at 65 mph. I average a constant 21 + for fuel mileage.
My opinion would be the one with 3.73. What you tow is so light the truck will not even know its there.

Running those tires, you'll be doing about 1650 rpm at 60 with the 3.73, 1800 with the 4.10's. That's about the same as my truck is running. Now, my rig is a 6.9 idi, not a psd, but it's pretty close. I find it good for economy, but it's not too good for towing. Now, I've still pulled over 15k on grades up to 7-8%, but that's getting down into 1st, and starting is very hard on the clutch. If it's just a hiway truck, go with the 3.73's, but for any heavy towing, or off road use, you'll want the 4.10's. I doubt 4.10's would give that much worse economy, either. It would be roughfly the same as a stock truck with a 3.54, which isn't bad.
-John

just for comparisons, mine is a 97' not a sd but i have 315's (35's) and a 5 spd w/ 3.55's. it runs about 2000rpms in 5th at 70 mph, which gets me about 17-18 mpg around tow, have not made any trips in it yet. plenty of power on tap, but will not smoke the tires up, at least not in 2nd. just some feed back.

The Superduty I built for my friend has 4.56 gears with 44" tires, and it pulls good. He does have some engine mods. He can spin the tires pretty easy. If your worried about fuel economy enough to ask this question then I would say fuel economy is more important than towing. Then go with the 3.73. You still wouldn't even know you had a jeep behind it. Unless your pulling heavy farm type equipment you will be fine.

Go with the 3.73's. I have the 3.73's and 35" BFG A/T KO's and tow a 36' fifth wheel trailer with no problem. I would like the 4.10's for my application, but if you are not towing any more than a couple thousand pounds, you don't need the 4.10's and they will kill your mileage around town.

Running unloaded, or just a quad in the back, I get 16-18MPG around town and have a best tank of 19.2 highway only.

I've got a '95 dually with 4.10's and a 5 speed. Gets 15.5 to 17mpg at 65mph unloaded. I'd go with the 3.73's if you want better mileage.