the gasket thickness they are talking about is on some pinion carriers actuall a shim and thats how they set the preload for the bearings... the ones that torque down though typically the spacer between the bearings is a crush sleeve...that crushes to get the preload to the bearings. if you tighten the nut to torque tight youll probably have to back it off a tad so the bearings arent to tight... just like a wheel bearing.
