I assume he is talking aftermarket. As far as I know the only trucks that came with 3.73's are the HD rams, which you could also get 4.10's. So which is it? Aftermarket? or factory in a HD?

 

That's what I'm saying is there are no aftermarket 3.73's for a chrysler 9.25 rear.

 

You've got a 4x4 so you need to put same gearing in front diff as in rear.

 

4.56's will not affect your mileage if you will keep your foot out of it. Mine got 17ish before and it gets 17ish now. Get a full master install kit with your gears and BE SURE the gears you order will fit your housing. Mine did not and the housing had to be ground down a little so they would fit. Not all gears fit all housings even if they say they do.
Also and most important, get a good mechanic - one who will stick with the project until complete and back up his work. Gears are a b!tch to set and not every Tom Dick and Harry who knows what a wrench is can do it. Ask and be sure to check references and credentials if you decide not to use a specialized rear-end shop I'm on my 3rd mechanic and hopefully 3rd time is a charm. Getting the backlash set is very important or you will have slack at the pinion and gear whine.
EDIT: One other thing, you might get a vibration since the driveshaft is turning faster. With 20" wheels and larger tires (over the stock 17's and 245's), you may be lucky and not get it.

 

4.56's are awesome.. Of course I have 35" tires, so thay were a must. Mileage went up about 2-3mpg on the highway with my big tires. Around town it went up about 1.5mpg.. They are the best thing I have done so far. If anything, I would have gone with 4.88's... But mileage isn't really important to me, if it were, I wouldn't have lifted my truck!

 

haha or drive a dodge ram period.

 

I have to agree ^^

If you care about mileage...what are you doing driving a truck? lolIm anxious to see how my new truck is...I ordered it with 4:10's. Shouldve got the power wagon...but I can get that next [8D]

Aound here...a gear swap isnt cheap. Had I know when I bought my current truck (04) I wouldve got the 4:10's. But I didnt have plans of jacking it and getting big tires. SO this time I did it right. And the kicker...a gear upgrade when you buy a new truck...its only 50.00Where if I was to swap the gears in my 04...it wouldve been 1500.00 -2000.00 Thats crazy!
SO I just bought a new truck lol. Seriously tho, its not cheap. Unless you really want some monster tires 35+ or plan on real offroading not mall crawling, dont bother.

 

Excellent Point!