Been a couple years but I believe this is the unit

https://www.doctordiff.com/8-3-4-clutch-type-sure-grip-powr-lok.html

My question is:

He hears a clunk in short turns. I don't think its the power-lok. I think its the street lynx suspension. Because the suspension is 4link with rod ends there is not the usual thick rubber insulation. The only thing I can think is that the inside tire drags when he turns sharp. If that tire bounces a bit and unloads/loads the suspension it might make the bang/clunk he's hearing.

Both my cars with power-lok 8 3/4 axles drag the tire on tight turns. But they never bang or clunk.