NOISEY 8 3/4 .Any advice

No i didnt take out the gears..the whole rear was bolted in..axels were slid in brakes and new plates and a new seal for the pinion..carrier [plug dropout ]was already in i didnt touch it except new seal and retorque a different yoke into it...makes noise under power and coasrting till i put in the clutch..then noise goes away till clutch is released and im under power again..tx..j

OK, did you buy the rear, have it set up by someone? Did you run it before you did the work, and was it quiet?

It sounds like ring and pinion howl to me. If the only thing you did was change the rear and it was quiet before that, then at least you have it narrowed down.