I’d look at the pinion bearings,
I agree,on/off throttle noise could be a loose pinion or bad bearing.A pinion race could have not been fully seated at install causing the pinon gear become loose after run-in.
Easy to check by dropping the shaft and shaking the yoke, checking turning torque with the axles out. Typically when that does happen, it makes a lot of noise.
Years ago I ran all the way up to 5:13's on the street without any noticeable noise. But that was 40+ years ago
As with many things, they don't make 'em like they used to.
