1986 1/2 ton with frozen rear differential side plug

I've never heard of a cover with a drain plug. BUT you could make one easy enough. Just drill a half inch hole, weld a fine thread half inch nut on the inside, and use a standard 1/2" oil drain plug and nylon gasket. I've done this to about 25 automatic transmission pans and it works great. On the other hand, no more often than it should need to be drained (never) why not just pull the cover, inspect, re-rtv, and stick it back on? But if you're talking about to do the fill and check chores, then I understand. Also, if you dig out the square hole and get all the dirt out of it, you should be able to remove that factory plug easy enough.

Fred,

The side plug (aka fill plug, you NEED to get it out!) is a 3/8" square head bolt. The easiest way I've found is thus:

1) Soak it in PB Blaster overnight. 2) Find a suitable length 3/8" ratchet extension bar and seat it in the plug. 3) Lightly tap the extension to get it all the way in the plug. 4) Put an impact wrench behind that extension bar (if adjustable, set to lowest speed/highest torque), REALLY lean into it (you don't want to strip out the bolt) and BBBRRRRRPPPP! Should come right out.

Doc