NOISEY 8 3/4 .Any advice

no not positive,but i sure dont remember the car making this noise with the 8 1/4 in there..but when i drove it after the switch it sure caught my attention..i was wondering about the trans being the culprit.supposedly this trans was gone thru also..that does make me wonder why the noise pretty much goes away when the clutch is pushed in and it coasts.just a slight pinion whine coasting...but in gaer with gas on it its pretty noisey on and off the gas..thanks j