So here it is, folks - confirmation that your oil pump can in fact be changed without dropping the crossmember. Here's the tale:

I've got an '84 244 with 140k on it. The oil pressure light was coming on at warm idle with transmission engaged - not good. So, for anyone who might attempt this feat, here's the method:

-following another post, built a jig to hoist the engine from the lift bracket
-removed bolts from steering axle to crossmember
-detached sway bar from frame (but not at wheels)
-snugged up engine from top
-removed engine mounts entirely, both from engine and crossmember end (no need to separate metal/rubber)
-lifted engine several inches
-removed engine/tranny support bracket

From this position (with oil drained of course) I was able to drop the pan enough to reach the two 13mm bolts on the oil pump, drop the pump in the pan (requires a good tug), rotate the pan and remove. I was then able to swap the transfer tube (with new oil seals at block and pump end), put the assembly back in the pan, clean pan and block and set a new gasket on the pan, rotate it back into position, and install the new pump. So here are some thoughts to make your life a little easier should you attempt this:

1. thoroughly clean the pan, the underside of the block, your hands, etc. before maneuvering the pan into place so you can keep that pan gasket in nice condition while you work - if the gasket's blown, you'll have to pull the pump again or else drop the crossmember.
2. try mounting the pump with the pan off before attempting it from inside the pan. After that try not to move the gear on top of the pump - that way the notch will be lined up when you install.
3. as easy as it seems to go on with the pan off, it's much harder with the damn thing on, largely because a)you've got about 3 inches tops between the block and the pan with the engine raised as much as it'll safely go, and b) with the oil pan partially off it's actually in the way of where the pump wants to sit. SO you're going to have to line up the transfer tube, get the pump gear into its hole and then lift the pan and pump at the same time (I did this by holding the pump from one side of the pan, the transfer tube (already connected to the pump) from the other, and pushed the pan up with my head while I seated it. From this point, DON'T LET GO - the pan is pushing on the pump and will soon unseat it before you get it bolted on.
4. on the subject of those bolts - tie strings to them when you install. That way, when you drop them and they fall into the pan, you won't have to pull the damn thing and start over.

12 hours and $130 later and my oil pressure was well within spec.

I'm at alexandergilson@hotmail.com. Email me if you need moral support. :)
-Alex