I totally second that flare wrench thought. It's been a few years since I've needed to drop the pan, but with lots of penetrating oil and careful brute force I always succeeded.

A flare wrench is definitely the best tool for such jobs, just like when cracking frozen fuel line connections. Flare wrenches don't just give a better grip and prevent slipping and damaging the nut faces, they better spread the force around the nut, not just on two faces. Unfortunately this is a large 24mm flare nut and anything over a 19mm-22mm wrench is quite uncommon as far as I can tell and not exactly cheap for such occasional use.

I can't remember if I actually did it or attempted and couldn't do it, but trying to get a couple of cheaters lengths on the wrenches (or using the wrench linkage trick, which I just recently learned) would seem like a good idea as long as you're using equal opposing force and don't have to put a wrench off angle to be able to add an extension. I've seen some extra long flare wrenches in catalogues with flex heads -that tool design would seemingly be ideal in this situation

This tranny connection has to be one of the worst to deal with in these cars especially as replacement lines aren't available and you risk damaging the trans fitting. The fitting for the transmission cooler line on the plastic sided rads is another one frought with danger if you don't use the counter hold method. That one I'm now more familiar with as for many years now I do all my trans fluid changes by flushing at the cooler lines -sooo much easier. As long I don't neglect the change interval and keep flushing until it comes out clear then I'm content I'm doing a decent job of maintainenace and haven't had any shifting problems even at well over 200K miles in both cars (having said that, I'm sure one of those devils will decide to misbehave tomorrow).

I'm sure you do this, but as a tip for others just starting to tackle such problems, having the wrenches closely offset, like 10-15 degrees from each other, allows you to put one hand over the other to squeeze them together with all your might. This is often easier and efinitely safer than trying to use one hand on each wrench at a greater angle. It can save a few knuckles too. Squeezing wrenches in this fashion also instantly stops the force once the bond cracks and the wrench handles become parallel in your grip, thus minimizing twisting of the tube after the bond breaks. Once you've cracked the bond between the nut and the threaded fitting, you can then take your time rocking the nut loose on the tubing with minimal twisting of the tube itself.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now