I'm tentatively looking to move to Alaska (from Michigan) I have a 24 ft enclosed trailer that my truck has always pulled like nothing even when filled to the brim in hilly northern Michigan...But I have no idea the terrain I will encounter through Canada. My truck is an 06 half ton Hemi with I'm quite sure 3.55 Chrysler 8.25. I'm just wondering if I'd be better off with a lower ratio to pull a heavy trailer THAT far. But once I get there, I'll prolly want my gas mileage (non-towing) back and want the 3.55. So an expensive rebuild is pretty much out of the question cuz I'd want it done again once I get there. The idea popped into my head of maybe getting the rear end and leaf springs off of a wrecked 3/4 ton and swapping it out for the trip then swap back once there. Haven't looked into it at all, no idea if it is swappable or not, it was just a thought. I was looking for thoughts/ideas from you guys. I considered the leaf swap cuz even though I have the weight distribution hitch that works wonders for me, I figured every little bit would help. Any thoughts, opinions, ideas, comments?? Am I being retarded and should just look for an older diesel truck, or is there a reasonable doable option with my truck?

I think you'd find that something like 4.11s (or stock 3.92s) would actually net better gas mileage in town. In Alaska, how much will you be on the highway?

To be sure of what you've got now, get your rear end ratio from the sticker in the glove box.

No sticker in the glove box. Even looked at the window sticker from dealer and doesn't say. But called dealer and gave VIN and were able to confirm it was 3.55...You say the lower gears would prolly be better around town, but would going with a permanent ratio change affect the MDS?

get me your vin and i can look it up for you.

Looks like you missed my edit by a few seconds...I had just got off the phone with the dealer looking it up with the VIN...thanks though

Another related question. Some people say that tire size can affect the gear ratio...While I see this as truthful on a very technical level...is there really an actual noticeable difference?

Changing the springs won't help this at all. Probably the cheapest, most easily reversible thing will be to get smaller tires. That will effectively shorten the gear ratio. What tires are on it now?

*EDIT* Whoops, missed the "rear end" part.

yes, smaller tires will effectively lower your overall gear ratio. but not by too much. and it might look funny

you will not be able to just swap out for a 3/4 ton axle without modification and fabrication.

going to a lower gear ratio (4.10s or 4.56s) will actually improve your gas mileage, give you more off the line torque, allow you to tow MUCH easier, allow you to tow MORE than you can with 3.55s, they will take alot of the load off your tranny, stop your tranny from constantly searching for gears, keep your RPMs running in the sweet spot for your engine, and make your truck much more fun to drive.

most people have a preconceived notion that lower gears will lower your MPGs.. with our trucks, that is simply not true! the only time your MPGs will suffer from lower gears is on the FWY IF you are driving 75mph or more for long periods of time. and you will get better mileage in town.

gears for our trucks are a win win situation! you cant really go wrong. more torque down low, better towing, and better mileage! if you dont believe me, do a search on here for gears, you will see that EVERYONE here with gears will agree with me.

yes there is a huge difference.
for example with a stock 3.73 gear ratio and if you slap a 38" tire on it when its stock tire is a 31" you have 7 inches more circumfrenece and will reduce your gear ratio to somwhere around a 3.20 or so ( not sure on exact... just to give a pointed example)

my friend runs a 4.88 gear ratio on his 40" tires for his duramax

Ugh, really didn't wanna go that route...but you've got me about talked into it now. Now I wonder which ratio would be best for my needs...