The 2000 ford ranger will require approximately 3 quarts of gear oil for the rear differential. the recommended viscosity for the rear end is75w-90 synthetic gear lube. there are many different brands and it does not matter as far as the brand goes but consumers have said that lucas oil or mobil 1 are the best quality lubricant for the rear end. the cost of gear oil will range from $ 7 - $ 15 depending on the brand and quality as some of them have additives and friction modifiers. you should make sure to check and change your fluid in the differential every 30,000 to 60,000 miles and if you drive regularly in rough terrain or towing a heavy load you should check it more often.
The rear differential fluid capacity for a 2000 ford ranger is 6 quarts.
Ford bother the 7.5 and 8.8 ford rear ends it should only take roughly 2 1/2 quarts 75w90 gear oil and if you have a limited slip rear end then you'll have to use a friction modifier additive along with it
2.5 quarts. fill until the oil level is at the bottom of the fill hole without leaking out. william, you are way off