After reading some of the posts, maybe I should clarify what I am saying.

My SVX had about 35k miles when I first changed the trans fluid. I pulled the dipstick and although it wasn't what you would consider "burnt", it did have a slight smell of starting to burn a bit. I then changed the fliud, filter, added an external filter and 2 16,000GVW coolers. This may have been a bit overkill, but from the horror stories I was reading almost daily on these transmissions, better too much than not enough as long as it worked correctly.

Well, after about 5-7k miles, the trans started shifting weird. Harsh shifts, jerking at highway speeds, etc. I assumed from the stories, and mileage, that it's days were limited. At the time, my brother worked at a Dodge dealership and was telling me about this new fluid Chrysler came out with that addresses those same problems in Chrysler vehicles where the average trans life was also about 40-50k.

I really had nothing to lose at this point. I either keep driving it the way it was, and replace the trans, or take a chance on this fluid and maybe it will help. So, I TOTALLY drained the trans and all lines etc and installed the Chrysler fluid. What a difference it made! The erratic shifting etc was totally gone! I have used it ever since without one adverse effect.

Now, the odd thing is, ATF + 3 has been ok'd for use in older Chrysler vehicles where Dexron was originally used. If the ATF + 3 is compatible with older Chryslers that used Dexron, why isn't it compatible with other vehicles that used Dexron?

So, it worked great for me, but if I had a new or recently rebuilt transmission, I would put what the manufacturer or rebuilder calls for in it and use the synthetic version. Unfortunately, I am almost positive Subaru doesn't recommend synthetic based lubricants at all if I recall, so either way, you are S.O.L. My response was to the original poster that had 99k on the trans and not had the fluid changed the whole time. Then I would put ATF + 3, but it is up to you.