Well with the last two cars I purchased the first thing I did was change the transmission fluid, oil, air filter, oil filter, and some other small stuff. But I never thought about changing the oild in the rear end, is it nessassary? And is it very hard? And how would I do it?

 

try this>>> http://www.fordf150.net/howto/differentialfluid.php If you have a 9" this makes it VERY easy

 

What year is your car? Mine (66) has to be drained with a hand pump, or with the axle out of the car. I think 67, maybe, they added a drain plug to the rear end. I could be wrong on that year though. I just had the rear end out though, so it was an easy change for me.

EDIT: That is the forum I use for my truck.

 

That is NOT how an 8"/9" rear is set up. There is no cover plate, the gears and diff are contained in the diff carrier which is bolted to the front of the axle housing.

If there is no drain (which there often isn't), you have to either remove the diff carrier and redo the gasket, or suck the fluid out the fill hole with a small hand pump..

 

you can go to any parts place and pick up a manual syphon pump for a few dollars. Looks just like a hand pump on a soap container, but larger. make darn sure you know if your dealing with an open, stock, or limited-slip rear. turn the a tire, if both turn same direction, you've got a limited-slip, and need to put in a bottle of friction modifier (6 oz)with the gear oil. open rears don't require the additive. once you syphon'd everything out, fill to the drain plug and your done.

 

Syphoning doesn't really do the job that draining is intended to do. You needed to remove the gunk as wel, which means you need to be opening the diff up and clean out the housing. The 8/9" rears are harder, but the time spent is worth while.