my biggest fear would be if it had a tranz failer and is full of shavings..
but have run a many used ones from the JY with out a problem
if its known to be good(trust who gave it to you) then run it
only thing I could see wrong with it is if it got trash in it from sitting and the snout not pluged
dirt or object fell in it maybe
you could have it open and checked and tweeked for some more stall but then you would be better off starting with a reman high stall TC to begin with
reman runs around 120$ at my local tranz shop
and I have a high stall /6 tc behind my 318 for a tad more stall
good luck either way