Cadet Mate - OSP700M Tool Changer Issue

We are having some trouble with our OKUMA Cadet Mate with OSP700M control.

For a long time the tool changer has been making a considerable clunking noise when the carousel advances. We're not entirely sure what was making the noise because it hits the bump stop and bounces slightly (1 - 1.5 inches) without making any real noise, then as it advances again into position it clunks. Lately it has been throwing alarms for limit switches in various positions and has not been running reliably. The last issue we have been dealing with is "Magazine not in retract position" alarms immediately as the carousel hits the retract bump stop. The carousel bounces and the SK6 and SK8 flicker, which must be causing the control to alarm as it loses signal for a second. The valve assembly that controls the advance/retract has two adjusters on it, which is what we would normally play with to eliminate these problems. They do not seem to be working as expected, so we decided to take apart and clean the valve assembly. That had no effect, so we started digging deeper and noticed an adjuster on each end of the advance/retract piston. By playing with those we can adjust how hard the carousel hits during the advance and retract stroke. We were able to lighten the advance a little so it isn't clunking and also not causing any alarms. The problem now is that, in order to eliminate the magazine retract alarm, the retract stroke has to be turned way up so it is slamming against the stop and not bouncing. This obviously is not a good solution as the thing is going to shake itself to pieces if we run it this way for long.

Is anyone familiar enough with this system to offer advice on tuning the ATC carousel so it has a soft advance and retract without bouncing? Does it sound like any parts in particular might need replacing based on what we are experiencing? Everything that we have inspected so far appears to be in good condition, though we are suspicious of the hydraulic damper after so many years of use. We are inquiring about pricing for that assembly currently. It is hard to know where to start to get it working right in both directions since there are so many variables involved in making it function. Anyone with experience, please help!

EDIT:
Also, one thing we found that was odd is that solenoid YV5 is activating and remaining active when it is supposed to, both during a tool change and when manually retracting the carousel. YV4, however, is activating properly during a tool change, but does NOT activate when using the manual advance button. This means that we cannot advance the carousel manually using the button on the control alone. We have to hit the button then turn the adjuster on the directional valve to allow the cylinder to advance. We traced wire 820 (YV4) in the control cabinet and found that it is powered with 24V during a tool change but is not being powered when the advance button is pressed. Wire 821 (YV5) receives 24V during a tool change AND when the manual button is pushed. The board seems to be capable of outputting the signal, so something else is preventing it when the push button is used. Any ideas?