Just received two line counters P/N TGT0538 from Southwestern parts. These are for two Shimano TEK500LC's. Tried to install them and found they bind against the plastic bushing the drive shaft fits into, once I screw the plate screws down that hold the line counter in place. I tried them on two other 500LC's I have in the shop for other customers and ran into the same problem. Also note that the zero button on these is orange and the original's all had yellow buttons. Wondering if anyone has run across this before. I have a call into to Southwestern about this and am awaiting a call back. I'll post what ever I learn.
Just an update. I modified the bushing the drive gear of the line counter sits in by grinding down the face quite a bit. That worked. Can now use the line counters. So seems like at least this batch (bought from Southwestern) may be on the high side for tolerances' and is causing binding of the drive shaft against the face of the bushing.