Significant Leak in front Left of Disco
 

A pretty bad leak started and the fluid appears to be collecting at the bottom of the washer fluid reservoir and dripping. It only leaks when car is running. The fluid is reddish brown, sometimes looks completely brown so I would think it would be power steering fluid? But I've been watching the power steering reservoir and the amount of fluid doesn't seem to be getting lower at all - despite puddles of fluid everywhere I go. Also, I don't see a visible leak from the reservoir/tubes while the car is running. There is a squelching noise ever 10 seconds or so and I'm wondering if it could be the power steering pump failing.

Video of link (noise can be hear at about 11 seconds in):
Any ideas on what it is?
If it is power steering fluid, is there a good way to stop the leak?

Check the top of the power steering box on the frame.
The lines going in and out have o-rings that can leak, as well as the lines to the pump and resivoir.

For a leak that size, I would expect to see a noticeable drop in the PS reservoir if that was the cause. Check the fluid level in the trans. The cooler lines run down that side of the engine.

It's looking like this might be the case. I have a 2001 so there's no way to check level without just adding some Dextron III and tracking, right?

Also, leak appears to be coming mainly from left side of cooler. Is replacing those lines a difficult job?

Looks like ATF to me. I have a similar issue, looks like a leaky sway bar bushing to someone who doesn't know any better. I removed the trans cooler lines and found no o-rings. I replaced those but the leak persists. I have to remove the cooler once again to see what's up, but your situation looks a lot like what I've been going through. No drop in the PS reservoir level on mine either. You video appears to be driver's side but unless you have an 04 then you have a temp sensor on the pass side of the cooler. Check that as well. As an added bonus, as a DII I have no trans dipstick. Whatever would you want that for...

Replacing the lines is the easy part. The dealer told me the list price was about $150 each however they were NLA. I'd be interested in hearing if you find a source.

Did you try jamming it back onto the pipe? Maybe you got lucky and the quick release collar loosened due to rust build up or something. The rust on mine (looks like yours) made removal really difficult. The trick to the collar is you slide it towards the engine to release it, while pushing the hose itself further onto the pipe. This allows the collar to push 4 "fingers' out of the way and the pipe can slide off. The hang up is the rust prevents the plastic collar from sliding freely.

For installation I found that putting vice-grips on the hose so that they didn't crimp the rubber but instead abutted the metal crimp collar gave me an advantage. I was able to hammer (lightly) on the vice grips and drive the quick connect far enough onto the pipe that it compressed the new o-ring and clicked into place. It was REALLY hard to get the hose to click on otherwise.

If you have a ruptured hose you may be able to take it to a hydraulic show and get it repaired, either by inserting a metal pipe inline to replace the comprised section of hose (if there's room), or by having them replace the entire rubber sections and supplying you with a new section of hose and quick connect on your old hardpipe that connects to the transmission.

Yep, a heavy equipment shop that makes hydraulic lines can repair or remake those lines.
Some people use atf in the ps too, so I would wipe everything off and be positive of where the leak is coming from.
A trans pan with a dipstick from a D1 will bolt directly to a D2 too. Both pans are the same other than the dipstick tube, and the tube is supported by one bell housing bolt.
I just bought one, and will swap them when I do a filter and fluid change.