Guys,

My 1999 Manual 5 speed 1.6L Civic has a kind of a whirring/grinding noise coming from the tranny when in 4th and 5th gears.

It is not a loud grinding but like when there is no oil between gears if you catch my drift. Only happend when I am accelerating but will go away if I diengage the clutch or take my foot off of the gas.

Is the tranny fluid low? How do I check the level?

Probably your throwout bearing. Mine's doing the same thing (no grinding though) and my last Honda made the same noise when the throwout bearing was going. :p

Might as well replace the clutch, pressure plate, and rear main engine seal while you're back there since you'll have to pull the transmission to replace the bearing.

Update:

Fluid was low by 400ml.

Topped it up and all is good.

Everyone with a manual tranny, check your tranny fluid level.

Update:

Fluid was low by 400ml.

Topped it up and all is good.

Everyone with a manual tranny, check your tranny fluid level.

where do i find the tranny fluid level and where does it locate? pic would be good.

Just go on and change your tranny fluid cause id say it hasnt been done and put some Gm syncro mesh in it...Its supposed to be some of the best stuff of there to stop tranny grinds and all..

Im about to change mine..