... The tranny shifts VERY firmly as it's going up through the gears, and in all gears. But it only does it on upshifts... The odd part is that it shifts smoother the harder I push it. The shifts are hardest under light acceleration.Trans fluid is very clean with no bad odor... I have read that these take a special trans fluid. Is that true on a model this old? Could they have put dex3 in?
You say firm and hard. That can be taken as quick and positive. Or it can be taken as clunky and jerky. If it seems problematic, it must be the latter.
The manual for my 2008, which is the same as a 2006, says to use Genuine Subaru Automatic Transmission Fluid Type-HP.
It also says:
"For optimum transmission performance,
only use the automatic transmission
fluid that is recommended and
provided by Subaru.
If the recommended automatic transmission
fluid is unavailable, Dexron III
may be temporarily used. If the Dexron
III is used continuously there will be a
noticeable increase in the vibration and
noise from the automatic transmission."
But I think for the 1999 model you are looking at, Dexron was OK.
Compare to our 2003 Buick, my 2008 Forester shifts more abruptly and less smoothly. But it still feels OK, so if you are suspicious of yours, there probably is a problem. It does have almost 150K miles and you don't know how it was treated or serviced.