Specs:
2001 Dodge Ram 1500 4x4 Sport Off-Road
5.9L
3" Lift with 35" BFG All-Terrains

I feel like the truck is low on grunt. I have heard that with 35" tires this truck needs a gear swap. What gears should I swap into the rear end with this setup to get the grunt im looking for yet keep the gas milage on the highway in check?

Also I have heard the the "Off-Road" package has a slightly different gear ratio to begin with... is this true?

Thanks for any help

 

I'd go 4.10s. If you had the 545rfe I'd say 4.56s due to the fact it essentially has a 2nd overdrive gear, but without that extra gear 4.10s will give you good low end grunt, better city mileage and not lose you much if anything on the interstate...

 

The Off Road package came with 4.10s....... so, that is what he currently has. He would need to go 4.56 to see any improvement.

And with the 5.9, shouldn't he have the 46RE trans?

 

Yes 46re. i started with the same truck and same tires. I loved my 4.10s on the highway and pulling trailers. 4.56 is a nice step up but you dont really notice that much. I mean each person is different but it wasnt that big a change to me.

http://www.4x4offroads.com/gear-ratio-chart.html

 

I didn't know that 4.10s were an option on 2nd Gen 1500s, thought my 3.92s in my '98 were it. I always thought it was 3.55/3.92 in 1500s and 3.73/4.10 in 2500s from the factory. Learn sumthin' new every day. I knew he only had a 4 speed, my point was in the 3rd Gens with the 545rfe you have that extra top gear so your mileage on the interstates with 4.56s don't drop much.
I wouldn't spend the $ on going to 4.56s from 4.10s. I don't think there is enough difference there to justify $1200 or more in expense. You'd notice it, but it sure wouldn't be a night/day improvement...