put some grease or something on the ring gear and make sure its meshing inthe center, thats all i did to check mine when I re-assembled it. Just make really sure the shims stay in the same place, i actually bought mine already in a pumpkin and the jackass' that installed it had the large shim in the wrong side so i took it all apart and used a new pumpkin and everything. BTW, hope you like your nismo, I hate mine. Selling for a tomei or ats.
