Hi there. First let me tell me about myself. I retired a few years ago (plumber so dont know much about vehicles but i am gettin there) and moved to Florida (wife wanted to) what a big mistake especially coming from Pa. theres nothing to do herre. anyway i am bored so i got the idea to just work on my Blazer (98LS, 4WD, 4.3, 2 door) thats why i have been asking so many questions. I have owned this blazer for about 12 years so now my project is changing differential oil but i cant find the fill plug on the front differential i have found the drain i think on the drivers side but dont see another one to fill. unless i am looking at the wrong thing. Anyway this site and people have helped me alot on doing things the the blazer and i want to say thanks again for the help

 

The fill plug is just to the passenger side of the center seam, on the front, near the vertical center of the diff.

You can see it in the picture attached to post #3 in this thread. It's the brassy coloured plug covered in oil.

 

Thanks, so to get this right the drain plug is on the passenger side.

 

oh i meant drivers side (old age) another question is walmart super tech a good gear oil?

 

Drain plug is on the driver's side, low down at the bottom of the diff, facing the driver's front wheel. The fill plug is on the passenger side of the diff, near the center height, at approximately a 45* angle from the passenger wheel.
I've used it, and it seems to be about the same as other gear oils.