changing my rear end oil(9inch) what kind and is it easy?

[sharkdog]

Just wondering what oil people are using in there rear end? I gandered in my owners manual but it just says ford hypoid gear oil and a part number. I'm led to believe it is 90w but I think that is next to impossible to find just wondering what people are using and conventional or synthetic(does it matter)? Also I know 9ich don't have a drain plug so is it easy to change i'v never done it?

70f-100 lwb 2wd c6 360v8

thanks again

[1972hiboy]

First thing you need to find out, is your differential open or has some sort of ( the ford name is escaping me ) "limited slip" type mechanism in it?
Open diff should just take conventional 80w90 gear oil. A locking type differential will require friction modifiers in the oil. the physical change isn't to difficult. With a drain plug absent, the oil will need to be sucked out through the fill hole with a device or vacuum operated fluid extractor then refilled.

[sharkdog]

thanks for the reply guess i'll have to find a tool to suck it out. i'm 99% sure it isn't posie but I guess i'll have to check the axle tag to be sure, but yes I do understand I need poise additive if it is.