So I've got this LWB recumbent cargo bike built up with a tandem style rear wheel. After only around 11 or 12k miles, the rear hub (FH-HF05, 7-speed cassete, 145mm O.L.D.) is having trouble. Cassette sticking with each rotation, as does the wheel which also suddenly began to squeak. Don't have any of the necessary tools up here to disassemble the hub right now, but wondering what could have caused this sudden failure and what parts I can use to remedy it. Thinking that maybe the axle got bent going over some rough terrain or whatever. But the quick release skewer still slides in and out easily, would that be possible with a bent axle? Flooded the cassette as best I could with lubricant, it spins better but still seizes. Also tried forcing some oil into the hub by dribbling it over the dust cap while spinning the wheel oriented horizontally; some black goo dripped out from the cassette end but the wheel doesn't spin any better, if anything the squeak is even more pronounced now and there is an occasional clacking/cracking sound when I try to ride on it. Can't coast of course.
The two bike shops up here would not have the proper replacement parts on hand, wondering where I could even find a new 145mm axle should that be necessary. Found a freehub body online, advertised to fit the 7 speed Shimano STX-RC and Acera-X. Not sure if that would be compatible with my FH-HF05, does anybody here know? Current cassette is a 7 speed 11-34T Shimano Megarange, guessing it is either an Ultraglide or Hyperglide, don't remember for sure.
Thanks for any help.