I have a 1979 F150 4x4. The build sheet states I have 3:50:1 Non-Limited slip rear axle ratio.
I believe this means only one rear wheel has power, which side I am not sure.
I would like to convert to LIMITED SLIP or TRAC-LOCK as the manual says, I am assuming these two terms mean the same thing.
There is a yard in town with a lot of old fords and 4x4's. What parts would I need to pull from a rear axle to make mine limited slip or trac-lock ?
I believe I have a Ford 9"-10bolt rear differential with a 3:50 grear ratio. Axle code on the vin number is 16.

Some one told me to pull the center parts out of a rear differential that is a 3L50, and also pull both axles.
Would I be able to use some of the parts in my original rear axle and add parts to make it limited slip, or would I be replacing all the inside parts, if this is the case, maybe I should purchase a whole rear axle and swap it out, what would you suggest. Also will 1978-79 bronco parts work ? I am only a backyard mechanic who has learned how to work on my Ford from manuals, so talk in user friendly terms, thanks oem78.

 

If any, what is the difference in Limited slip/Trac-lock/Posi traction ????

 

posi traction is a gm term(so i was told) limited slip is what ford calls it,trac lock is what type of unit you could find in your diff housing (it is a type of limited slip/posi traction carrier) other makers are detroit locker,auburn, power lock,etc. if you are not familiar with inside a differential,and how they need to be set up preload of pinion gear,backlash,tracking of gear faces,etc. i would suggest you buy a diff that is a bolt in unit.complete axles are not that hard to remove and replace,but if your not sure how to regear a diff,you could ruin some expensive parts. if its a 4x4 and you are also changing the gear ratio,you will have to also change the front diff ratio to match the backs ratio.

 

sorry,i didnt notice your dealing with a 9 inch rear axle.if your diff is a ford 9 inch in the rear, you just have to swap out the third member,(center drop out carrier) and replace it with a ls carrier that is all together entacked and complete.providing its the correct gear ratio,and your not intending a gear swap to change the ratio.make sure the axle spline count is the same on the new carrier.some were 28, some were 31 (and i've heard there are some that are 35,but don't quote me).the axles won't inter change.you could count your axles splines, and when you remove a diff from a donor vehicle count the splines on that axle to make sure its the same. if your doing a gear ratio change in a 4x4 you still will need to re gear the front diff as well. and that wont be a third member drop out style carrier,so your back to bearing preload ,pinion depth,gear tracking issues. sorry for confusing you if i did.