Hallo, Has anyone came across a swing gear lubricating grease mixed with the swing motor gearbox on a Cat 330 D2l? The oil is SAE 50 gear oil. I found a very thick oil coming out of the gearbox breather. It is very thick as in a mixture of oil and grease. I couldn't think of the grease going up from the swing gear to the gearbox as there'sno pressurised grease in the swing gear. So, cleaned the gearbox and changed the oil, thinking that the fault could be from the oil. But it happened again. This time, we took out the swing motor gearbox and changed the seals at the bottom of the gearbox. (One facing down and the other facing up) The one facing down (which is responsible for stopping the grease from going up was a bit soft). I'm still not convinced grease going up the gearbox as there is no too much grease pressure in the swing gear. This scenario never happened to my 322b which is over 25 years old. I heard it happened to other 330D2l as well. Do you think it is a design fault?
i suggest to remove the 4-bolt inspection cover for the swing gear grease bath (should be located in between the lift cylinder mounts) and take a photo to show what the grease level is.
Thank you Nige.
Hi Nige, Sorry it took long to take the pic. I also measured the hight of the grease and it is about 10mm. But, this is after we did the swing gear maintenance where we removed the old grease and put a new one. Before the maintenance, the high of the grease was definitely above 10mm.
If those photos are a true reflection of the grease level then in my opinion you put far too much grease into the swing gear cavity. The level of grease in the compartment under that cover should only be just high enough that the bottom surface of the swing pinion makes light contact with the surface of the grease and creates "swirl" or "wave" patterns as the upper frame rotates. It is not the intention that the swing pinion is used as a "food mixer" for the grease. I wish I could find a photo that shows what the grease should look like but after a lot of searching I can't find anything. I think there should be somewhere around 25mm thickness of grease in the base of the compartment. The best way to determine is to measure the distance from the bottom surface of the pinion to the floor of the compartment and then add maybe 2mm.
Thank you for your reply Nige. I think the pic is not showing the level of grease clearly. I've attached another pic. When I measured it from the base, it is about 10mm.
If you swing around to the left a couple rotations, then swing 180 degrees back to the right you'll spot the grease ball that the pinion is pushing around. It should be about the size of your fist. A lot more and your pinion will act like a gear pump and force grease up past the lower pinion seal and into the swing drive.
In that case even though you are only measuring a thickness of 10mm the grease layer in the compartment is still much too deep. The bottom face of the pinion needs to be just "kissing" the surface of the grease, not swimming in it........ Sorry if I confused you with the 25mm thickness I mentioned above. I must have been thinking more about larger size machines.
Thank you very much for your support.
You're welcome. Again apologies for the confusion regarding the 25mm measurement. Obviously your machine requires much less than that.