Ghetto eagle, actually. Recently installed sunrace 11-50 11 speed cassette, gx eagle derailleur on a new der hanger, gx 11 speed shifter, with existing 30t mrp chainring. it doesn't want to upshift from the 42t to the 36t, but what really driving me nuts is theres a rumbling sound in the 3 largest cogs, almost like every chain roller is rubbing a tooth somewhere, but only under max crank load when climbing steep, cant reproduce it in the stand. b-tension is set according to the gap spacing tool that came with it and I followd srams instructions regarding chain length. Except for that one upshift it shifts fine everywhere else. ive never had a problem setting up a rear derailleur in 12 years of riding/working on my bike. Any ideas anyone? Could it be the chainline? the chainring is in the "middle" 104 bcd setting on an older shimano xt triple crankset, about 51 mm chainline which seems to line up with the 5 smallest cog . Thanks.