What gearing would work best?
 

A diesel with a max power at around 120 hp at 4300 rpms and 170 ft/lbs torque at 2400 rpms. the tranny would probably be off of an 80's dodge or ford 4x4. i want to run 33"-31" tires. i was going to try to run the dana 60 but my friend said that, that would be a bad setup and i would lose power. any ideas?
~kabe

what vehicle?
 

how much does it weigh? what are you going to use it for? stick or auto?

tom w

How much does it weigh?-engine OM617 and a jeep so not very much.

Preferably auto.

use- everyday driver, and a little offroading.

Does anyone have any ideas?

I want to start looking for parts.

Thankyou

~kb

so if the jeep
 

engine has a max rpm similar to the benz the stock gears will prob be good. figure out the rpm on the highway that will allow cruising at around 3000 rpm and you will be pretty good. if you arent going to use on highway then go as low as you can find prob.

the friction loss from a big diff like that wont be that great but the axle will be very heavy and it will make the jeep ride like a log wagon.

tom w

Is there any specific gearing i should be looking at

~kabe

MPH = (rpm x tire diameter)/(336 x axle ratio x trans gear ratio)

Tire diameter is in inches.

How do I find out the Axel ratio and Trans gear ration?

thankyou for something that i can use from now on.

this is something proven right?

should i go by the max speed of which i want to go? or should i go by the normal speed i'll be driving? I normally drive around 60 MPH. not usually on the highway except in the summer for vacation and i have to take this thing camping.

Thanks

~kabe

so what is the
 

operating rpm of the stock engine? are you going to use stock size tires? if not then the diameter will have to be calculated. we can't guess what you want to do. you need to decide what size tires you want.

personally i always would recommend keeping as much stock as you can. non stock parts will cause a host of problems that you never thought of.

so if you give us the op rpm of the stock motor and some of these other things we can help.

tom w

How do you plan to put the MBZ diesel and the Mopar tranny together? You also won't "loose power" with the Dana 60, you just don't require that much strength. What year is the Jeep, and what axles are in it now?

I want to swap out axels because i am going to be lifting the jeep, losing power in turns and possibly tipping over easier. wider axels decrease the possibility of rolling over.

-I have a couple of friends that have (own) tool and die shops that will help me make plates and shafts for whatever i want for free. you can go to you rnearest tool and die shop and they'll probably charge a small amount for the metal but that is it.

-so does anyone know how to find axel and tranny ratios?

I think the tranny your talking about is a NP435 4 spd. The high gear ratio is 1 to 1. Dana 60 probably came in a bunch of ratio's so you would have to look at the specific axle and count the teeth and do the math. I think ratio's available would be 3.55 3.73 4.11 so choose which would work for you.
This link will help you decide the effect of tire size and rear ratio
http://www.csgnetwork.com/automotiveconverters.html

which link should I be looking for because I have been looking around and haven't been able to find the right one.

~kabe

Try this one http://www.csgnetwork.com/gearratcalc.html
diff gear ratio calculator On the 4 speeds you were talking about 4th gear is 1 to 1 so this should work just fine. If you decide to do this please post here and let us know. I'm trying to talk a friend into dropping one of these motors in a Range Rover County.

Forget the D60 it's overkill for 120hp. If you're plan on running 33's you'll need a gear swap in both axles unless you're building a poseur rig for the street. I think the stock gearing in an early YJ with the 258 is something lame like 3.08's. 3.08's with 33's plus the additional weight of the tires is going to make that YJ a slug. You'll prolly want to upgrade the brakes also considering the tires and extra weight of the dsl.
I'm curious as to what you're using to mate the Dodge whatever trans to the MB motor? I'm gathering parts for a similar swap using a 240D motor, MB trans and divorced 205(GM) tcase but my CJ8 has a 10" longer wheelbase so the divorced tcase length isn't an issue.

edit: Guess I didn't answer your question huh? With 33's and a 1:1 final trans ratio I'd go 3.73's or 4.10's. If you use the NV4500 trans w/OD I'd go 4.10's or even lower(numerically higher). What's your intended use...daily driver, rock crawler, mud runner?