I have a early GC2310 My serial number is nt4045. My father managed to rip off the oil filter so i had to take it all apart to fix it. well i fixed that and before reassembly i found this thread. I looked at my pump and gear and sure enough it is so worn it could shear at any time. so i am going thru the runaround with massey on this. I ordered a new gear from jacks it was $75. massey redesigned it so it engages a full 20MM on the splines vs the old amount. I am trying to get them to give me a pump or a big discount on one. I have tried to find a new shaft but no luck as of yet. i would make one but i am having a hard time finding the right cutters for the splines and the gear with it being metric. The bad thing is my machine only has 326hrs on it.