I just happened to be looking at my rear differential, but I could not see a drain/fill plug.

Can someone tell where it is located. I wasn't inspecting too closely. But, I don't see it on the differential cover---is it on the other side, near the driveshaft??? The Haynes manual shows it on the differential cover.

I have a 3.55LS diff.

 

The fill plug faces the driver's side on the front half of the axle housing center section (you check the level here too). There is no drain plug; you drop the pan, install one, or suction it out.

 

You'll have a bugger of a time getting the fluid sucked out using that hole, I wasn't even able to attempt it as the 1/4" tube on my lube pump wasn't large enough to get by the gears.

It's easier and more effective to drop the whole cover, but that's if you intend on changing the fluid.

Bambino

 

https://www.f150online.com/forums/sh...p?threadid=664

Solves all of your rear diff fluid changing problems.