I am in the process of repairing a 2000SY Doosan and almost have it ready for work.
The final challenge is diagnosing and repairing the live tool drive. When running free, it is quiet. After engaging a tool, it rattles loud enough to have you lunge full speed for the reset button. I have pulled the turret cover off (separate thread - it was not easy) and found that a couple of o-rings were damaged and allowing coolant into the turret . It is a bit rusty and mucky but It cleaned up well. I don't see that any critical surfaces are damaged yet. Special thanks to @dhardt for the assistance getting this far.
With the cover off, it is easy to pinpoint the source of the rattle from the drive shaft interfacing the live tool holder. Visually, it appears that there may be a minor alignment issue. I ended up pulling the drive out before I thought to measure the gap at the coupling. The gears visually look good, the assembly rotates smoothly, and does not have any play that I can detect with my hands. The shaft has about .001" runout when measured out of the machine which is more than I expected but perhaps not enough to make it rattle like it is. Before removal - the runout was closer to .004" while engaged with a toolholder. The drive slot shows considerable wear - which allows for a lot of slop when a live tool is engaged.
Initially, I was going to replace the shaft just because I already had it apart until I realized it costs $650. I better make sure I am making a sound decision.
Attachment 409538
Coupling wear.....
Attachment 409540