i havent worked with differentials yet on my truck but i know theres limited slip, posi or trac-loc, power-loc, detriot lockers, and air lockers like arb lockers. is there anything im missing? and also i tried to order them in terms of strength if im wrong i would be glad if any one corrected me or had an opinion about any of these differential setups. and also i just a quick question that i dont know, do the gears in ur front and rear differentials have to be the same like 4.10 in both or can u have them different?

 

Your list pretty much covers most everything. And about them being listed in order of strength, its hard to list them. I have a friend with a 76 with limited slip front and rear and his are almost rock solid. But his are tightened up a lot too. And to the part about different gear ratios, that can be a good way to burn up a t-case. Say you have 3.79 gears up front and 4.10 in the rear. The rear driveline will need to turn a lot faster than the front, binding the case up. Its like having a twin stick np205 and running the rear in low and the front in high and trying to go down the pavement road. Bad things can happen

 

What are you trying to accomplish with your truck? Each type of traction additive has its benifit and drawback.

 

"Posi" (positive traction, GM term) is just a limited slip.
You should also know that the trac lok, and the power lok are also only limited slip units.
These clutch type limited slip units were tossed around and used in various axles.

 

open diff, then ls (or limited slip), then detroit locker, air locker,then spooled. all in order of traction they provide. trac loc, power lock, are steels and friction type ls units. trac loc is a 2 spider unit. power lock is a 4 spider unit (stronger than trac loc) choosing the style to install will depend on the needs you have . for most guys a good power lock is all you will need. air lockers are great for rock crawling and daily use applications because you can engage them as you need them. spools are strictly an off road use deal, you would not want to use them on the street.they lock both axle shafts together with no chance of slipping for corners. hard on drivelines and tires on high traction situations. there are many brands of diffs and carrier/ gear sets to choose from,i could keep going ,but thats the basics. hope this helps.

 

ok thanks sipsmithers thanks for the info that makes sense with putting gears in mt differentials. and thanks 75F350 and hotroddually for the info. that clears up my differential situation and questions for now. and also im trying to rebuild my 1978 ford F250 and make it a mud hole destroying, trail busting beast but also take it out once in a while and show it off. so it will be off road 80% of the time and on the road 20%. so im thinking maybe a trac-lok or power-lok idk what do you guys usually use? or what would you use in my situation?

 

I would choose air lockers.

 

You talking about a front or rear application?
Everything probably depends on how bad you intend to beat on your truck. A real automatic locker will have the greatest strength, and reliability.
A good LS unit in the front will save parts and break less stuff than a full blown locker.
The power lok is probably the strongest LS unit that you will find. Trac loks tend to be a little on the weak side.

 

On your ford the front and rear ratios will not be exactly the same but close.
Example 4.10 4.09 3.55 3.54 more than this will not exactly burn up your transcase something has to grenade immediately.

 

Can't beat a Detroit in the rear.

 

ARB air lockers are pretty good, but at a price. I priced them for my 9" rear and d44 front at ~$850 per unit.