MusicBro

Hey everyone. Got a 95 F150 axle code 18. 3:08 gears, non limited slip. It's got 150,xxx miles on her and I think it's time to change the fluid in the diff. What type should I use? Do I need an additive even though it's open? Thanks guys

BLDTruth

80w90 gear oil, and you don't need additive. You will need to make a gasket out of rtv and let it dry....or you can purchase a gasket at an auto shop for $5-10. Pull the fill plug, pull the cover, drain the old oil, clean up the cover and all of the old gasket on both surfaces, put new gasket on, tighten cover (don't overtighten, and do it in an opposite pattern - top, bottom, left, right, etc.), fill back up with oil until it dribbles out of the fill hole, plug, done.

choate

I used Valvoline 80w90 that had the limited slip additive already in it. You can do that if you have a LS differential. If not then you dont need it. Sorry if I missed that. Anyways word to the wise as mentioned. First make sure you can get the fill plug out first. Otherwise you won't have a way to fill it back up. Also, start with the bottom bolt first when putting the cover back on. I didn't do the last part and ended up with a tiny leak at the bottom that I think has been fixed but not without putting RTV all the way around the outer edges of the whole diff after already installing a gasket. Good luck. Its not hard but laying on your side cranking bolt can be hard on a guy but maybe you are young and won't feel anything

MusicBro

Alright sweet thanks fellas!