The "2T" means that it's the 2 track mastering version; the tape records a stereo signal on two wide tracks in one direction only; a standard "hifi" recorder will record two narrow stereo tracks in one direction, and two narrow stereo tracks in the opposite direction (four tracks total, but not going in the same direction).
If the output sounds muffled, buy a reel of new tape; calibrate the deck for the new tape, and try it again. But do this after you've looked at and cleanded the heads, guides and rollers. If you're not comfortable with doing the calibration yourself, take it in... there's still lots of guys who can do this for you.
Hopefully the heads are in good condition... if they're worn badly, you'll hear it.