So I need a new rear end in my 94 pickup 4x4 and I was thinking of putting a prerunner rear end in it because from my understanding the prerunner has a locker in it correct me if I'm wrong though. But how does the locker work? And would I be able to put it in my truck and have it work? Thanks

 

Putting the rear axle in and getting the locker to work is just basic wrenching and wiring the control for the locker that works via a electrical solenoid.

something is waving for attention in the back of my mind that the rear axles are different widths I might be wrong !!

Get the tape measure out and measure things

Then you need to match the gears in the front differential to the ones in the new rear

 

Awesome I'll check the widths out. And how do i find my gearing I have no tags or numbers that I can see on the rear diff or the front. Is there some sort of old school way to find out? My dad said you can jack up one side of the rear end and mark your tire and driveshaft and turn the tire and count the driveshaft rotations but he doesn't remember exactly how to do it

 

Find the axle code. It's probably right. Click the following links for more info.
http://4x4wire.com/toyota/faq/vin/
http://home.4x4wire.com/erik/diffs/

 

Counting driveshaft or pinion rotations is highly subjective,
Best to pull the third and count the pinion teeth and count the teeth on the ring gear, divide your ring gear count by your pinion count and it will give you your gear ratio.
The chances of a taco prerunner ratio matching your stock 94 gear ratio is not go9d...

 

Not all tacoma prerunners have the e-locker. You have to find a truck that has the TRD offroad package.
The axle is about 3'' wider per side. A few company's sell a stand alone e-locker harness that makes wiring pretty simple. I would also strongly recommend getting a locker motor guard, as a replacement from toyota is not cheap.