According to the 2001 Ford Ranger Owner Guide :
Front Axle Lubricant :
( Motorcraft SAE 80W-90 Premium Rear Axle Lubricant )
( 1.7 liters / 3.6 U.S. pints )
repair manual fora front differential on a 2001 ford ranger edge
They are on the inside, next to the differental bearings. The entire axle has to be dissassembled to replace them.
On the front of the intake manifold
Dana 35
157- 213ft lbs
Its located above the rear differental, mounted on the underfloor.
In the front passenger footwell , by the kick panel
In the right front passenger footwell , by the kick panel.
I don't know if your Ranger is the same but on the 2001 Ford Explorer the 4X4 module is located behind the right front passenger kick panel
According to the 2001 Ford Ranger owners manual : The 2.3 L and 3.0 L take SAE 5 W 20 The 4.0 L takes SAE 5 W 30
The 2001 Ford Ranger owners manual shows it as being in the right front passenger footwell by the kick panel
firewall 3 - 6 2 - 5 1 - 4 front