Differential noise

[347GT]

I have an Auburn pro locker diff. Just put new 4:10 in place of the 3:73. There is some knocking when turning but only when turning moderately sharp to sharp and mostly when turning right. There is no noticeable noise or vibration when driving straight or on curves. Noise is mainly on tight turns. Btw its an 8.8 in 85 Stang and has c-clip eliminators.

 

[347GT]

Changed out the royal purple to inexpensive 80w90 napa gear lube and 4oz of friction modifier. All noises immediately went away. But wait, the next morning the noises came back slightly, so I drove around the church parking lot doing backwards figure eights. No more noises but the church goers found it quite odd. So, it takes cheap oil , going to church and driving backward to fix a noisy diff.