I can tell there's something wron by the look of the main rotors. The problem is that I don't know what is wrong with it. I will be replacing main shaft and I would like to know what spindle shaft is. Then if anyone could point me where all the replacement/repairing instructions are, I'll highly appreciate it. If not, could someone please PM me the instructions?
I'll also find the following helpful:

1. What else to buy along with main shaft and main gear (and bearing removal tool)?
2. How can I inspect if the shaft is bent or etc. I can't physically see anything wrong with the heli yet.