The variable speed transaxle in my troybuilt is junk. I think its a '98 model,with the 18 h.p. twin cylinder and the axle model is 618-0307c......I've seen a few on ebay with the model no. 618-0073 and 618-0070,plus a few others but none with my numbers. Anyone know the differences or if they will work? I have another '96 model,17 h.p. with the axle model 618-0307 and it whines like crazy but at least the axle didn't wear through the housing like the 18 h.p., and its what I mow with now.Thanks for any info I can get