The final drive of the komatsu PC300-3 and other dash 3 excavator is equipped with a double planet gear sytem. I remember there was three marks on planet gear and on sun gear. These marks should be used to asssemble the final drive. On the other hand, the same design is used for the swing machinery but without any marks. Anybody have the answer for this?
Those finals were called a differential drive as I recall. They quit using them when they went to the Dash 5 model of machines. Each gear set had a mismatched tooth ratio that would only work with each gear set timed. The planetary gears on the output end had numbers one, two and three stamped into the gears. The sun gear on the output also had the stamped numbers and those numbers had to match the numbers on the planetary gears. One on the sun gear had to match a one on one planetary, two on the sun gear had to match the two on the next planetary and three had to match the three on the last planetary. The odd thing was that once the planetary gears were in you could remove the sun gear and put it back in any way you wanted. The only other machine I've seen that used that type of planetary were Hyster rollers for the drum rotation. They worked OK when the machines were used as excavators but when we converted them to log loaders they had a huge failure rate. They never wore out, they broke up into shards worse than shattered glass. I used to get broken ones in to be assessed for rebuild as the dealer I was working at had an exchange program. There would be anywhere from five to twenty five of these units to do a month. I still have the scars on my hands from rebuilding those things.