The easiest way is to find a good rear end from a junk yard and replace the whole unit. Rear ends are cheap at u-pull-it junk yards.
If you really have to rebuild it get a service manual - too complicated to explain here. If you rebuild you will have to spend some money on a dial indicator and some specialized tools if you don't have them.
If the rear end whines on decell (downhill, foot off the gas) it needs a ring and pinion, in other words, a differential overhaul/new rear end.
repair manual fora front differential on a 2001 ford ranger edge
What is the timing for a 1998 ford ranger 2.5l
My Ford Ranger is a 1998 4.0 ltr V6.
No, the cab was lengthened in the 1998 model year.
what is the axle gear ratio for a 1998 ford ranger 4x4 4.0l?
need locations of steering column brackets on a 1998 ford ranger
The wheelbase of the 1998 Ford Ranger Supercab is ( 125.7 inches ) according to the owners manual
Bank 1 is the passenger side of your 4.0 liter V6 in a 1998 Ford Ranger
on the driver side on top of differential hub
98 ranger and what else?
5W30