2005 Legacy 2.5i /4eat trans possibly "baked'

[Legacyguy005]

Hi all well to update my previous post-today I finnaly got some time to "really look this legacy over-an investgate a few things-since i jus got this car...engines a 2.5 i  stock-car has had ALOT of the important things done allready -head gaskets were done last aug.-new cats...[both]-gotta great deal on this cos i went in knowing its probably gonna need a tranny-so  since i was running it today-[an cleanin it up-lol]-the car has gears when cold-it will run&move on its own power...but..... all the while-[from startup-and beyond]-thers a noise coming from the area of the frnt dif/tourqe converter section-its a "low sort of "gurgle/whine....almost like a power steerin pump kinda racket-i actully took a close listen to the ps pump...nada....its def comin from under the car-about 20/25 minutes of idlein th motor....dropped her into drive-trans engauged...but MAJOR slippage...had to bring it up a few hundred rpm from idle to get it back to where i parked it-trans fluid is pretty dark [black cherry/brownish]-an has a slightly burned smell-now Im assumeing this tranny is "baked"-car has 170,000 on the clock-and overall in very nice condition... my plan is to get a good used trans an get this baby rolling again-couple things Id like to ask....is how do i determine [and if i find a matching # tranny should i ?]  the gear ratio? the trans is a 4EAT  and the car has "sport shift'-the transmission tag number i found on top of the bell housing is as follows..... TZ1B7LCAAA-2D........And just so everybody knows Iam a 35 year mechanic cars/trucks/rec vehicles-ect  an I have to admit....iam tempted to just do a teardwn on this thing-an re-build it.... but i figuer if buy another tranny-i can get it done a little faster-id install it myself-this my 3thrd subaru- I started w/a 1990 legacy-put 1 engine in it before superstorm sandy killed it on me-then i gotta 97 impreza L  4dr-[right now thts my reg car]-now ive just got this legacy-an "I WANNA DRIVE IT-LOL" so any advice will be a help-thanx  Bobby : )

[montana tom]

The TZ# is the important #to know.   Here on the west coast I would call foreign engines for a Japanese take out transmission.