Gearing question

[Coonburger]

I was pretty dead set this winter id be throwing in 5.13 gears into the ol' dodge and thats the lowest id go but after talking with some guys on a pure 2nd gen dodge forum everyone keeps telling me to run 5.86's with my 40's. Now i trust their opinions to a extent i mean they have had a lot more experience with these dodges than ive had. one guy said he beat the hell out of his truck and broke everything else besides the gears. Still though. i was wondering what ualls opinion would be. The truck is gonna become a pure toy here next year and probly trailered to anywheres it goes so driveability aint to much of a concern. I am just worried cuz i do like to play in the mud/sand dunes it being way to geared to do any good. I am doing a ton of research online trying figuring it out. i was already planning on upgrading the axle shafts with the gear change, along with the driveshaft. The weak link i think after that would be the transfer case which would have to wait for a bit. the gear change and etc is gonna definitely put a dent in the pocket book. let me know ill take any constructive ideas.

[Serious Offroad]

Use the gear calculator at Grimm Jeeper. easy to use pull-downs to select your driveline components and tire sizes for a side x side comparison of different combinations.

Alloy Shafts are always a great upgrade.

[xaza]

Not too familiar with whats available for the big dodges but sounds to me like you would benefit most with either a gear reduction box added to current t-case or a new t-case that offers multiple gearing choices.

Atlas Transfer Case - 4 Speed Units | Tech Vault | Advance Adapters

NWF BlackBox Underdrive Unit

[Hypoid]

Are those other guys running the same engine and tranny? Ideal gearing will keep your engine operating at, or close to, it's peak torque output.

[RidgeRunner]

What Mike and Frank said, use that rear ratio calculator and go for the gears that get you closest to the stock combination.

[Coonburger]

ran the numbers in that calculator its about a 9mph difference between the two for a given rpm. 65mph down the road in overdrive id be running 2400rpm's with the 5.86's and 2100 rpms with the 5.13's , not a huge difference really in my eyes. after running the calculator definitely doesn't make those other guys sound insane. The dodge guys are running same motor and etc. as iam. I know different people different preferences lot to think bout thats for certain.

[xaza]

(in my mind) When it comes to toys, peak engine torque is not as important as slow enough wheel speed. Gotta go real low to gear an axle for that. At that point same said gear ratio is too low for driving much anywhere else. One of the smart guys here can correct me if I do my math wrong. A t-case with 2.72:1 gearing with a reduction box with 2.72:1 = 7.4:1. As long as reduction box and t-case do not have the same gearing you will get 4 different ratio combinations

curious to see what you do. You plan on staying with 40's when it becomes toy?

[RidgeRunner]

Another thing to think about is strength. I don't know much about 1 ton axles but the higher ratio, the smaller the pinion gear. Smaller pinion = weaker gears is what I've always heard but it may not be that big of a deal on the beefier axles.

[Coonburger]

dana 70 has alot bigger pinion then a 14bolt so thats in my favor but the pinion size for a 5.86 is roughly a lil smaller than a 3.55 from what i understand strength is also a concern but the dodge guys that run that gear have beat them to hell in truck pulls and never broke the gears. ill stay on 40's for a bit thinking maybe jumping up to 42's after i shove the front axle forward a bit bout 2inches is safe without moving everything in the front end well see how it goes.

[Hypoid]

Coonburger previously posted:

[xaza]

Thats kinda what I thought and now I only get about 8 mpg with my inline six

[Coonburger]

there all out east like georgia and **** dodges aint as popular as jeeps lol

[Coonburger]

hypoid i run pretty much run that rpm now with my 4.11's cuz i cant run overdrive and iam working the truck so hard.