I'm somewhat of a newb with manual trannies so please bare with me .

Two weeks ago I finished installing a T56 in my '94 Camaro. This wasn't a rebuild, but a new tranny from Tremec.

I took the car for a drive and it shifts very nice as it should and I am very pleased with the results. However, when I engage the tranny into 5th gear (i.e. release clutch with shifter in 5th gear position) I hear what sounds like a grind. The grind only lasts for a brief moment just as I release the clutch pedal.

I have about 150 miles on the tranny thus far. I also have a Pro 5.0 shifter in place of the OEM unit.

Could anyone tell me what is causing this noise?
Thanks in advance for any suggestions.