Ok guys now I have my front and rear gears and the front carrier what do I need to get now

 

Can I thread jack..?

I'm curious as to the difference between the diff gears. Larger number=stronger or faster?
I have the Chrysler 9.25 in the rear with 3.5 gears and the Dana 40 in the front. What does this mean exactly?

 

All 1500s, bar some kind of custom conversion/upgrade, have a Chrysler 9.25 rear axle and a Dana 44 front axle.

A lower numerical gear ratio (also known as "higher gearing") usually means better MPGs, but less low end grunt for towing. However, when it comes to pickups, you also have to factor in tire size. The maximum tires you should run on 3.55 gearing is 285s/33s, otherwise you cause excessive wear and tear to the *cough* faithful *cough* 46RE transmission. And your truck will be a bit of a dog with 285s/33s and 3.55 gears.

3.92 or 4.10 gears are about perfect setup for 285/33s, equivalent to the factory 225s/245s with 3.55 gearing as far as decent low end grunt with good MPG (as good as these trucks get, anyway). Larger tires, 35s/36s, 4.10s are a minimum requirement without causing wear/tear issues. 4.56s+ are recommended.

RPMs will be higher on the highway the lower the gear ratio (numerically higher). 4.56s will give you more RPMs then 3.55s at highway-type speeds. And the higher your gears, the lower your top end speed/grunt drops. But your low end will pick up more.

 

Thank you. I understand better now.
My truck has 265/75R16 tires on it (factory optioned upgrade from 245 in the Laramie Pkg.) I have a set of 245/75s I'm about to put on because my tires are wearing thin (especially inner edge of front-alignment issues I'm guessing) and winter is coming.

How do the different sizes affect speed(RPMs)/mileage? The new tires are the same height, just narrower...

 

They have less surface area contacting the road though, because they are narrower, which = less rolling resistance, which = better MPGs with stock gears, bar of course 4x4 use or snow or a strong headwind or etc.

 

That's what I figured. Thanks, Jason.

So I'm correct in assuming, based on what you said, that my tire/gear combination is best suited to my use- daily driver with an occasional bed load and rarely a trailer.

 

Yes. There are also the factors of weight and size involved. Obviously a smaller tire will have less rubber and therefore lighter weight. The difference between a 245 and a 265 is minimal, but when you go from the stock 245 to something like a 33" or 35" tire, it is something to consider. The extra weight of the wheel/tire combo will put more stress on suspension components and the larger diameter will stress the braking system. In extreme cases the higher unsprung weight can cause serious issues like tire hop and excessive suspension cycling that can lead to a loss of vehicle control. It also takes more power to turn those heavier tires and the reduction in gear ratio from the taller tire coupled with the loss in power can turn a spry Dodge into a dog. Regearing can bring back some of that lost pep, but it will do nothing to counter the effects that extra weight put on your suspension and braking. That's why components and mods be selected to match not only your truck's capabilities, but the way you drive it.

 

It always amazes the heck out of me when I see these idiots driving around with super lifted rigs that you need a ladder to get into and I don't think they have taken all this into consideration. It seems like they have a hard time getting out of their own way. It also always seems to be FORDs or CHEVYs.

 

To be fair, I've seen some Dodges that way to. But there are a lot of Chevys in my area like that, or F-250 Fords. You glance at the tread on their big a** tires, you instantly can tell they're highway tires. Makes me laugh.

 

Big tires have their place. This is the only way to raise the axles and gain greater ground clearance. Unfortunately, most people do this to their trucks strictly for the looks. I was one of them. I had 40" tires on my '79 Power Wagon, a 6" lift kit and 3" body lift. I loved the look and my truck got lots of compliments, but after about a year of broken driveline parts, crappy handling, expensive repairs and not really being able to use my truck off-road as I had been previously with 33" tires and a 4" lift, I finally saw the light. Ever since I have been very conservative in modding my Jeeps and trucks. The result is they last longer, break parts less often, cost less to maintain and handle much better. This truck would probably look great with another 4" of lift and 36" tires, but as I don't want to complicate my life and ruin what is now a great truck, I will leave it alone. I may add 33" tires when these wear out, but as I don't want to make loading my dirt bike in the back any more difficult, I may just leave it as is.