hey..

my '93 900 has 150k on it.. i've only had it for less than a year and haven't driven any 900's besides this one.. it's a maual shift, and i find that when the rpm guage gets anywhere beyond the 2 it gets real whiney.. not like a gear slipping kind of whine, but like "you better put me in the next gear!" kind of whine.. so i just try to accommodate that but i wonder if there's something to be fixed about it or if this is just the way the 900 transmission is... most cars i've driven have more give between when you shift up, ya know?

Unless you have dog cut gears the transmissions are generally quite.
The usually start making noise right before the big bang...
Sounds like a synchros problem?

I am not an expert on transmissions but was getting some whine in 3rd and 4th before mine went.

I would suggest checking the fluid levels before anything else.

I'd drain the gearbox - try to strain the oil through a hunk of screen - that way you can evaluate how much metal is coming out - then re-fill it with fresh oil (regular, MTF, whatever) to the correct level and see if that makes any difference. If you don't know when the oil was changed last, this is as good a time as any.
It could be the gears, it could be the differential - heck - it could be an alternator bearing or some other accessory going south - if it's engine rather than road speed based. Check your belt tensions, give a listen to your accessory bearings with a stethescope (including the AC compressor clutch) - perhaps you'll be lucky and it'll be something external - and you'll still have nice, fresh oil in the gearbox!

Steve