Checking Rear Differential Fluid - 1987 500CD

[Dave Marshall]

I want to check the fluid level in the rear differential/final drive of my
1987 5000 CD Quattro.

I am embarassed to say, I can't see where to oil fill plug is.  I am lying
under the car with a trouble light and no luck.

There are two plugs that look like they are drain plugs.  Both are on the
bottom.One is close to the front of the rear differential and the other
about mid way to the back.

Any help is appreciated.