Differential

[79Bronco]

Figured I'd jump in on this thread and clear things up.

Here are the different kinds of differential, with pros and cons listed.

Open Differential-

Pros- Cheap, usually already there, hard to break

Cons- Power goes only to one wheel, the wheel with the least amount of traction. Imagine having one wheel on the ground, and one wheel sticking up in the air, you can mash on the gas all you want, but the only wheel getting power here will be the one off the ground, and you're not going anywhere.

Locker (Detroit, Eaton, Yukon all make "lockers")

Pros- Most lockers use specialized gears (think worm gears) or clutch plates to "lock" the axle shafts together. This basically means that if you have one wheel off the ground and one wheel on, the locker will force both wheels to spin, thus delivering power to both wheels, and getting you out of your sticky situation. Street performance, it will behave like an open differential until it senses that a wheel is spinning (not getting traction) and then it will activate, delivering traction to both wheels.

Cons- Some lockers (old school detroits especially) will have a loud "clunk" when engaging and disengaging, it is nothing to worry about, but may take some getting used to. When hitting the gas around turns, you may not be happy with an engaging locker suddenly, and unexpectedly locking up on you. There is a learning curve to driving a truck with a locker, but it is not as "dangerous" as running a spool in a street driven application. Expensive (500-1000 new)

Spool - Essentially welding your axle shafts together (not literally) but a spool will force an equal 50/50 amount of power to each axle shaft, regardless of wheel traction, turning, etc. People like spools because they are cheap. Others argue that the money you save from going with a spool will be spent later on the parts that are broken because of a spool. Regardless of what people say, spools put a tremendous amount of strain on your axle shafts, bearings, u joints, etc. Some people do not care because they build their axles with enough strength to hold up to this kind of abuse. When driven on a street, a spool will not unlock the axle shafts, this means when you go to turn, your inside wheel will literally "hop" off the ground while turning.Pros- spools are stupid cheap (think 50-80 dollars)

Air Lockers- By far the best choice if you have the money; although, a point can be made that electronic lockers are just as good. These are selectable lockers. Meaning when driving on the street, you will have an open differential.

Electronic lockers- function much the same as air lockers without the compressor tank. They are selectable when you need them. Also very expensive, but not as expensive nor as much work as air lockers. (you dont need a compressor, tank, and plumbing)

Limited Slip (posi, positrac, trac-lock etc) - basically a system of clutches that allows only a limited amount of wheel spin before activating the other wheel. What I mean, is think of a 60/40 limited slip. It will deliver 60 percent of power to a wheel with the least amount of traction, and 40 percent of power to the wheel with the most amount of traction. (the wheel with the least amount of traction would be the wheel up in the air in the previous example) It is like a semi-locker. Some people really like them for offroad applications in trucks that are driven on the street. They are cheaper than selectable/air lockers, and provide a good compromise of traction and strength. A limited slip will need to be rebuilt after a certain amount of use, as the clutches do wear out. These are great diff's for on-street use, because they provide a fair amount of traction at a reasonable cost.

There are also other lockers such as cable lockers, but this is a good general summary.

[Reg_Cab_Slammer]

So for me do you think I should go limited slip? I want something in the back that I can spin both tires with but use if I offroad. Also some people are saying I have to replace both differentials, is this true?

[CleanSierra]

Your front should already be setup for torque applied to both wheels evenly. It's when you change gears in one pumpkin that you have to change them in the other, otherwise: Asplosions!

[Reg_Cab_Slammer]

Pumpkins? Lol

[CleanSierra]

Another word for differential(housing)

[CleanSierra]

Example: You can't run 3.73s in the front axle and 4.11s in the rear.

*Edit- ^^^ those ring/pinion ratios are NOT Dodge or Dana specific, they are GM

[Reg_Cab_Slammer]

Ok so if I end up wantin lower gears in my back end, ill have to do that up front?

[CleanSierra]

Ok so if I end up wantin lower gears in my back end, ill have to do that up front?

Correct, and as I said WAY back, don't attempt to change the gears yourself. You have to get the lash DEAD nuts on or you'll have a noisy rear end, or one that wants to blow up on you. Changing gears is NOT for a lot of guys. My dad turns a wrench for a living, but won't tackle a gear change on his own, and he's the best mechanic I've ever seen(obviously I'm a bit biased).

[Reg_Cab_Slammer]

Ite, well I'm not real mechanical lol. And nahh I just wanted to be able to spin both tires, so ill prolly either get that powertrax differential or a limited slip then leave everything else alone. Thanks guys

[79Bronco]

I think you should spend your money elsewhere. Your argument of "I want a traction aid so I can do burnouts" is very immature and provides no real practical application. Also, you have a half ton dodge, you shouldnt really be doing any serious offroading that will require a traction aid. You have an independent front suspension, a very poor design for an offroad truck. (not bashing all IFS systems, just saying that the factory one from dodge is especially weak)

Go with a limited slip, it will perform best on the street where the truck is driven 90 percent of the time, and it will offer slightly better results offroad.