2006 Nissan Sentra • 135,000 miles

The manual transmission makes a whining noise that increases with RPM's and goes away when the clutch is pushed in. Supposidly the fluid was changed at 110K or so, but the last garage said the fuid level port/bolt was rusted and they could not get it off to check the level. Is this (the whining gear sound) a start to a problem, or is there another place to check the level or add tranny fluid? It is not a grinding sound or harsh (That sounds awful! Type sound).
December 7, 2012.

It could be the fluid level but it sh=ounds like it could also be the throwout bearing.
To reomve filler hole to check level soak and wipe and soak overnight as many times as possible with PB Blaster or WD 40 if you can't find it.