I'd have to side with the professional flushers on this one. Aamco http://www.aamco.com/ (not Amoco!) will flush the trans for about $115. The thing is, they backflush it, so that debris can flow backword through the trans and out into the machine. If you drain and fill, you won't get most of the fluid. If you "idle and suck" new fluid in, you are still flowing forward, and a lot of debris can get jammed up in the valve body and other places. You also run the risk of running dry if you are not careful.

The filter is a screen. Leave the pan gasket in place, it will save you the trouble.

Power Backflushing is the best way to change the fluid. Unlike a radiator flush, which doesn't do a lot compared to draining and filling twice, the trans is different.

Don't forget to change the transfer case and the diffs as well. And don't forget the LSD additive for the rear (I think most VX's had Limited Slip Differential).

Happy motoring.

Nate