my gear ratio is stock 3.73 with an auto. I just recently put on 35x12.50 nitto mud grapplers. What gear ratio will be best 4.10 or 4.56. I use it to pull a 30 ft toy box and a 26 ft boat. Its also a daily driver. My buddy has the same truck, but stock tires with the 4.10 ratio and its power it awesome. Thanks in advance

 

Id go with a 4.30 ish if you can find it for your truck.

 

With 35" tires, Id go with 4.56's. That's about equivalent to your buddy's truck - stock tires with 4.10's.

I would only use the 4.10's if you werent going to be doing much hauling. Performance wont be quite as good, but your RPMs will be much lower on highways and you'll get better mileage.

 

4.10s are fine. My brother is running 4.10 with 35s on his 04.5 CTD and its plenty. If you had a 5 speed OD or a gasser then 4.56 would be the way to go.

 

I run stock 4.10's with 37's and I like 'em just fine. I turn ~72 MPH @ 2K RPM.

 

If you go with 4.10s that will put you pretty close to where you started, itd be like havin factory tires. It is not an absolute but for every inch of tire you increase in hight increase your gear ratio by 0.1

 

I have 4.10s, an NV5600 and 35s (315s). Sometimes I wish I had a BIT more power towing, but that is what 5th gear is for. I can cruise easily in 6th on the highway but pulling out is a littler slower than I'd like.

Of course a chip will fix that

 

Do they make gears in between 4.10 and 4.56?

 

I wouldn't bother changing the gears. When towing heavy just lockout overdrive and you'll be fine.

Carl

 

Get a good converter. If you don't plan on adding power, you can get away with just a good, tight converter and be fine.

 

I would stay with your stock gears. i have 315 all terrains with 4.10 but i wish i would have got the 3.73 for better fuel economy

 

Why would you want to change gears? A 35" tire isn't very big, If your concerend about power towing, then just crank up your engine.

You counldn't pay me enough to change out my 3.55 gears, I love em, and I have 39" tires.

 

You can always make a taller gear lower by downshifting.

But once you're in high gear, you can't make a low gear higher. Think about that when turning 2800rpm @ 60mph.

I personally think the combo of 315s and 3.55 (equivalent for whatever truck) is PERFECT with a 6-speed.

With an auto trans, you may want a little lower gearing, and the taller OD of the auto may let you get away with it more. I think I'd prefer 4.10s with 35s and an auto. Certainly no lower, though.

jlh