The 90s have straight cut gears in the ZF which produces some gear whine, especially in 1st and 2nd, I find (in my 90 as well). AND, it comes when the clutch is out and goes away when the clutch pedal is engaged. But, if you noise is the opposite, then throw out bearing comes to mind - except seems unlikely with so few miles.
There are many members in your area that might be able to drop by your location and assess the sound with a learned ear. Aside from that, have you changed the transmission fluid yet? Changing the trans and differential fluid - may or may not improve the sound (if coming from the trans), but then you can check that off the list and you'll know that isn't the issue.
Perhaps Mark Horner or one of several other local Texicans can give it a listen.
And, given that gear whine is the nature of the beast in the 90 to mid 92s, if that is all it is, the fix is turning up the radio or installing headers w/o cats!
(kidding ya!)