I have a '76 f150 9" rear with 3.89 gears and was wanting to service the fluids in it.

I have never jacked with a rear diff. before and was wondering what the easiest way would be to drain the fluid.
(Since there is no drain plug)

Do I actually have to pull the third member to drain the fluids.

Thanks, Al

According to my manual and past experiences it is suck the old fluid out through fill hole with a manual suction pump device or pulling axles out part way then removing the whole third member.

If you are going to suck it out, make sure you do it hot or you will be under there until next Christmas.

i use my mityvac vaccuum pump to suck out the gear oil on mine. the fill plug hole lets u get in the housing with a small hose and remove the oil. parts stores sell em.they work good for empting brake master cylinders and ps pumps too. the ring gear is in the way if u try to stick anything in the 3rd member, but just jab the hose around till it goes down to the bottom of the housing. i thought about installing a drain plug on mine, but im too lazy anymore,lol.

Thanks for the input; I was considering the pump idea and thought it would be alot easier
than pulling the third member, but someone had told that a hose would get caught and that I would not be able to get it out if I tried.

This sounded kind of strange to me so I thought I would just ask and confirm.

Thanks for the reasurance; Al