Toyota BZ 6 speed Sprinter

I just had my gear box tuned, Replacing the Pressure Plate, Disc, Clutch realease bearing and Crank Shaft Seal.
Now I have a whistling noise coming from the Gear box area, when pressure is applied to the clucth pedal the noise goes away, but tapping on the lever on the top of the gear box , engages and disengages the noise.
Cn any one Help with this problem

its hard to say, maybe its the realease bearing
I think iv had the same whistling your talking about and it tended to happen on cold nights after been run hard, could be your gearbox oil is abit thick or something aswell.