Replacing differential oil and correct oil to use

Hi! 4runner 1999 2WD 3RD GEN.
1. Why is replacing the differential oil so much more cumbersome than say engine oil?
2. If the oil is specified as hypoid full synthetic gear-oil API GL-5

$55 Valvoline SynPower SAE 75W-90 Full Synthetic Gear Oil 1 GA

Valvoline SAE 75W-90, would this ensure the right oil for this service in Houston?
Thank you very much.

 

1. It's not - the hardest part is getting the bolts off if they're stuck - but it's as simple as such a procedure can be. You're just changing the oil on a metal sphere with drain and fill ports. It was actually harder on my Sorento since you had to drop the spare and get an extension to access the fill plug through a metal support.

2. 75W-90 will be fine.

 

It's more difficult because the diff plugs have a longer time to seize up between changes than engine oil. That oil will be fine.

 

ICEBEAR, TREKKER thank you!

 

One thing that's very important to remember is to make sure you can remove the fill plug before you pull the drain plug to empty it. If you can't fill it back up, draining it is a forlorn action.
Once the fill plug is out, it's safe to remove the drain plug to empty it.

It's a good idea, if a plug is difficult to get out, to chase the threads before you put the plug back in.
IMHO, don't use any kind of thread locker. No locktite red, yellow, whatever.

Good fortune!
Pat☺

 

Thanks.