I just rebuilt my 904 and with the four new disks and steels the 1/4 inch steel that the big snap ring goes on top of won't fit. The new stack is to tall. I can get the snap ring in if I use a new thin steel in place of the thick one or if I take one friction ring and steel pack out. What's the lesser of the two evils here? One less pack or the thin ring? This is in the rear most drum. The front drum is fine for some reason.