when you say slop in the lowest gear I presume you mean up and down movement not side to side which would be bad. I am not familiar with the Harken you have but every other NEW winch that I have played with has up and down play in all gears AND drum. All forces should be applied at 90% (or actually 80-85) so this isnt a factor. If you have any side to side it would be bad. As you bearings appear OK I guess it would sudgest the brass tower is deformed.........
Seems unlikely with the way these things are built, man they are nice. Ive been playing around with "solid works" an engineering program and it is so cool to see how forces are distributed around different shapes. Low stress areas Kinda corresponds to where the cutouts are on the winches...... go figure
Do you know what a bearing looks like which is 'burnt'?
Look for blueing marks on the roller bearings. Also excessive play in the races (metal holding the bearings)
Take the entire tower apart, and check each fit of the gears as you re-assemble.
It may be that it is something as simple as the final screw inserted into the fairlead not being seated or tightened correctly
We broke the pig tail off today in our second day using the GRCS. I had a good size piece of wood almost straight below the block. It was holding on by a hair and I need the guys to crank it up one inch and it would swing loose in a mellow swing. I am not certain what I told them but they both pulled on the rope straight away from the GRCS and bent off the pig tail where it is welded to the frame. I hope we don't break anything else anytime soon.