cam94z28

I recently received my EZrun 60A + 6000kv motor combo, and decided to throw it in my old RC10B2 before I rebuild/strengthen the tranny in my Evader EXT2 to put it in there.

It initially had about 1" to 1.5" of play in it, where I could rotate the spur freely, with the tires held, before it stopped moving. I checked and made sure the play was in the entire slipper assembly, all the way to the back plate. On my final adjustment, I tightened the slilpper nut all the way down, so I could back it out and set it, and something popped inward. Afterward, there was virtually no play in the spur. I mounted the motor, and took it out for some fun. When I came back in, the play had magically returned.

Any idea what could cause this? I believe I noticed a similar problem in my EXT2, at some point, but I had to take it apart due to a bent top shaft, and it was fine once reassembled.