Drive wheels are only a few months old. they are not consistently pushing the wire through. Machine gets relatively regular use by students. The wire got bent after the drive wheels but before entering the gun hose, due to a student clogging the tip and trying to run the wire. I removed the wire entirely and re-ran it. the spool was tangled, but is not now. what else can I check to fix this?

Saws - Lincoln Electric - Power MIG 255 XT Welder