75W-90 synthetic gear oil
maybe
The front differential is a full synthetic gear lube. If you have to ask where it is then you should probably take it to a reputable dealer or Lube shop. The actual specs for the gear lube are in the owners manual. Whoever wrote this has no clue either. The front diff has a 26mm bung on the right front side of the diff casing. See photo page 5-47 of 2003 owners manual
85W90 gear oil and add a bottle of positive trac. lube also.
75 80 90 gear lube is fine
Usually you fill it to the bottom of the hole.
There isn't a drain plug. You will need to remove the diff cover to drain the gear lube.
No, that is gear lube for a differential. Use mercon.
The speed sensor ring is in the differential case in front of the ring gear. To get to the unit you will need to remove the differential cover and drain the lube which requires replacement along with the cover gasket. Check to find out what lube you need to use and if synthetic is required. If you are not familiar with differential or transmission work you may want to get an estimate from a transmission shop or your mechanic.
The front axle uses 80W90.
Depends on which you have and what you use the Truck for. Standard Differential, Rear Dana 135.....GL-5[3] All Temps......75W-140 Amsoil Severe Gear 75W-140 or SAE 80W-140 Synthetic Gear Lube Controlled Slip Differential, Rear Dana 135.....GL-5*[3][4] All Temps......75W-140 Amsoil Severe Gear 75W-140 Controlled Slip Differential, Rear Dana 80.....GL-5*[5][6] All Temps......75W-90 Amsoil Severe Gear 75W-90 Standard Differential, Rear Dana 80.....GL-5[7] All Temps......75W-90 Amsoil Severe Gear 75W-90, SAE 75W-90 Synthetic Gear Lube or Severe Gear 75W-110 These recommendations are for a 2004 F350. Standard Differential, Rear Ford.....GL-5[7] All Temps......75W-140 Amsoil Severe Gear 75W-140 or SAE 80W-140 Synthetic Gear Lube Controlled Slip Differential, Rear Ford.....GL-5*[7][8] All Temps......75W-140 Amsoil Severe Gear 75W-140 Standard Differential, Rear S110, S130.....GL-5[9] All Temps......75W-140 Amsoil Severe Gear 75W-140 or SAE 80W-140 Synthetic Gear Lube
Depends on which you have and what you use the Truck for. Standard Differential, Rear Dana 135.....GL-5[3] All Temps......75W-140 Amsoil Severe Gear 75W-140 or SAE 80W-140 Synthetic Gear Lube Controlled Slip Differential, Rear Dana 135.....GL-5*[3][4] All Temps......75W-140 Amsoil Severe Gear 75W-140 Controlled Slip Differential, Rear Dana 80.....GL-5*[5][6] All Temps......75W-90 Amsoil Severe Gear 75W-90 Standard Differential, Rear Dana 80.....GL-5[7] All Temps......75W-90 Amsoil Severe Gear 75W-90, SAE 75W-90 Synthetic Gear Lube or Severe Gear 75W-110 These recommendations are for a 2004 F350. Standard Differential, Rear Ford.....GL-5[7] All Temps......75W-140 Amsoil Severe Gear 75W-140 or SAE 80W-140 Synthetic Gear Lube Controlled Slip Differential, Rear Ford.....GL-5*[7][8] All Temps......75W-140 Amsoil Severe Gear 75W-140 Standard Differential, Rear S110, S130.....GL-5[9] All Temps......75W-140 Amsoil Severe Gear 75W-140 or SAE 80W-140 Synthetic Gear Lube