I rebuild and upgrade these transmissions and have 1st person hands on knowledge of how and why they fail and how to fix them and prevent them from failing--some of which I'm happy to share.
1st off) The oe transmission cooler in the radiator is nothing but a hazard. Don't use it. It is very restrictive even if it isn't clogged and easily does clog. Seriously, don't use it. It used to be common on these forums for people to advise not bypassing it theorizing that the radiator will heat the atf in the winter and bring it up to operating temperature and that that wouldn't happen otherwise. However, a stand alone transmission cooler installed in the drivers fenderwell with its own fan controlled by it's own thermostat has proven to allow the atf to come to operating temp quickly and then maintain the atf at an optimal 176F. This option is much safer and is likely to greatly extend the life of your transmission. There are kits available for doing this such as this B&M kit from Summit:
http://store.summitracing.com/partde...5&autoview=sku
2nd) The subaru atf for the phase1 4eat is a very good fluid and especially good for the phase 1 4eat. Unfortunately many dealerships don't know what they are doing and try to sell you the wrong fluid. The new fluid is not equivalent. You want SOA868v9240
3rd) It shouldn't be necessary in your transmission but in my transmissions or transmissions with my performance valve bodies I have my customers use lube gard atf protectant (not some other product by some other company they are not equivalent). You can use either lube gard platinum:
http://www.lubegard.com/automotive/t..._platinum.html or lube gard atf protectant:
http://www.lubegard.com/automotive/trans_atf.html These additives will further modify the friction profile of the subaru atf to reduce friction with lower apply pressures and prevent binding of the transfer clutch at low speeds.
Is your car an early production 92/is the transmission out of an early production 92? It sounds like your reverse clutch might be burnt out which I've only seen happen on the early production 92's.