This should be left up to a pro due to backlash has to be set as well as pinion depth and load on the bearings. If it's done wrong it will make noise and or howl all the time.
There are different axles but none of them are do-it-yourselfer projects. Anyone can unbolt stuff and pull parts out but setting up the bearing preload, ring gear backlash, and side gear clearance requires special tools and procedures. Some axles require a housing spreader to get the differential assembly out and back in. Over-stretching the housing can permanently distort it.
Pinion gear depth and bearing side clearance must be carefully adjusted. You'll need a shim kit and you'll have to install the pinion gear numerous times with different select-fit shims to get it right. All of these adjustments affect the tooth contact pattern which has to be checked. If the contact pattern is wrong, you will have noise right away, after many miles, and / or only when accelerating or coasting.
Setting up a differential is a specialty field that few professionals are experienced enough to handle.
Here is the info if you wish to give it a try: Drive Pinion
Remove differential case.
Mark the driveshaft flange and the pinion flange for correct alignment during installation.
Remove the four driveshaft bolts, and disconnect the driveshaft. Wire the driveshaft out of the way.
CAUTION: The driveshaft centering socket yoke fits tightly on the rear axle pinion flange pilot. Never hammer on the driveshaft or any of its components to disconnect the yoke from the flange. Pry only in the area shown with a suitable tool to disconnect the yoke from the flange.
Using a suitable tool as shown, disconnect the driveshaft centering socket yoke from the rear axle pinion flange.
Install a Nm (inch-pound) torque wrench on the pinion nut, and record the torque required to maintain rotation of the pinion through several revolutions.
Remove the pinion flange and pinion nut.
Remove the rear axle drive pinion seal.
Remove the rear axle drive pinion shaft oil slinger.
Install the special tool and, with a soft-faced hammer, drive the pinion out of the outer pinion bearing and remove the drive pinion through the rear of the housing.
Remove the drive pinion collapsible spacer and discard it.
Using the special tool, remove the pinion bearing cone and roller assembly.
NOTE: Do not remove the pinion bearing cups from the carrier casting unless the cups are damaged.
Remove the outer differential bearing cup with the special tools.
Remove the inner differential bearing cup with the special tools.
Position the special tools and the inner and outer bearing cups in their respective bores.
After placing the inner and outer bearing cups in their bores, place the special tool on the inner pinion bearing cup.
Place the special tool on the outer pinion bearing cup.
Install the special tools.
Tighten the special tool to seat the pinion bearing cups into their bores.
Using 205-DO55 and 205-153
Drive the outer pinion bearing cup into the rear axle housing, using the special tools.
Using the special tools, drive the inner pinion bearing cup into the rear axle housing.
Setting pinion depth
CAUTION: Whenever new cups are installed, new differential pinion bearings must also be installed.
NOTE: If a feeler gauge of the specification shown in the illustration can be inserted between a cup and the bottom of its bore at any point around the cup, the cup is not correctly seated.
Make sure the cups are correctly seated in their bores.
NOTE: Apply only a light oil film on the pinion bearings before assembling the tool.
Assemble and position the special tools.
Tighten the special tool to the specified rotational torque.
NOTE: The special tool must be offset to obtain an accurate reading.
Rotate the special tool several half-turns to make sure of correct seating of the pinion bearings, then position the special tool.
Install the special tool.
Position the special tool.
Install the differential side bearing caps.
Install the differential side bearing cap bolts.
NOTE: Drive pinion bearing adjustment shims must be flat and clean.
NOTE: A slight drag should be felt for correct shim selection. Do not attempt to force the pinion shim between the Gauge Block and the Gauge Tube. This will minimize selection of a pinion shim thicker than required, which results in a deep tooth contact in the final assembly of integral rear axle assemblies.
Use a drive pinion bearing adjustment shim as a gauge for shim selection.
After the correct shim thickness has been determined, remove the special tools.
Using the special tools, press the pinion bearing and pinion shim until they are firmly seated on the pinion.
Place a new drive pinion collapsible spacer on the pinion shaft against the pinion stem shoulder.
CAUTION: Installation without the correct tool can result in early seal failure. If the rear axle drive pinion seal becomes cocked during installation, remove it and install a new one.
Install a new outer pinion bearing, rear axle drive pinion seal and rear axle drive pinion shaft oil slinger.
NOTE: Coat the lips of the rear axle drive pinion seal with Premium Long-Life Grease XG-1-C or equivalent meeting Ford specification ESA-M1C75-B.
Place the special tool in the pinion seal bore and drive the rear axle drive pinion seal into place.
Install the drive pinion in the drive pinion carrier bore from inside the rear axle housing. Seat the drive pinion with a plastic hammer.
Lubricate the pinion flange splines.
Use SAE 75W-140 High Performance Rear Axle Lubricant F1TZ-19580-B or equivalent meeting Ford specification WSL-M2C1 92-A.
NOTE: Disregard the scribe marks if a new pinion flange is being installed.
Align the pinion flange with the drive pinion shaft.
With the drive pinion in place in the axle housing, install the pinion flange using the special tool.
Position the new pinion nut.
CAUTION: Under no circumstances is the pinion nut to be backed off to reduce preload. If reduced preload is required, a new drive pinion collapsible spacer and pinion nut must be installed.
CAUTION: The pinion flange holding tool must be removed before preload readings can be taken.
Using a suitable pinion flange holding tool to hold the pinion flange, tighten the pinion nut.
Rotate the pinion occasionally to make sure the cone and roller bearings are seating correctly.
Install a Nm (inch-pound) torque wrench on the pinion nut.
Rotating the pinion through several revolutions, take frequent cone and roller bearing torque preload readings until the original recorded preload reading is obtained.
If the original recorded preload is lower than specifications, tighten to the appropriate specifications for used bearings. If the preload is higher than specification, tighten the nut to the original reading as recorded.
Install the differential case.
Position the driveshaft and align the mark on the pinion flange.
CAUTION: The driveshaft centering socket yoke fits tightly on the rear axle pinion flange pilot. To make sure that the yoke seats squarely on the flange, tighten the bolts evenly in a cross pattern as shown.