I have been going thru my Project machine - Komatsu PC75UU-2 and fixing things, and doing all the maintenance to it. Thursday I drained the final drives, let sit overnight in the heated-70 degree shop. Friday I started filling them back up. What a pain in the neck! Even heated the oil up in hot water and still took forever to get then filled. There is just no place for the oil to go - the side of a gear or something is only about 1/8 away from the fill hole. So what tricks do you guys use to do this?
A couple of tricks; Don't try to fill it with a funnel, use a hand pump. If a gear is over the hole, rotate the drive a fraction. The gear will move. If the drain hole is small enough, stick the nozzle of your pump in there and fill it from the bottom up.
You should have three plugs. Orient them so on is on top, one on the bottom and the last straight across. Take the top and side one out and pump oil in the top until you get oil just starting to come to the threads on the side one. Cmark is dead on about rotate to make sure the hole is uncovered on the inside. You do know those final drives use 30 wt. engine oil, right?
I will have to look again, but I don't remember there being a third plug, they are hy dash drives. I think my problem was not rotating this till I had an open space to fill into. Where I had it rotated to there was just no room for the oil to flow in freely. John C. 30wt motor oil. Yep, I do have the manuals for this machine. A pump, and rotating till I find an open space will be in order next time!
When I got my 331 Bobcat recently, I found the right final drive gearcase empty ! Just red dust inside. I filled it and ran it some, then drained the red oil out (85w-90). Refilled it expecting leaks but see none after running it awhile. Hope I got lucky. I called the Bobcat place in Hattiesburg, MS to inform them of what I found. They were supposed to check all this....ha ha. A joke.
No oil! that really does not make a guy feel too good! Would rather see dirty oil than none!
The whole motor oil in final drives, swing gear and hydraulic tank is a bit strange to me. In discussions with our oil supplier who supplies oils to all brands of heavy equipment. He has worked in the industry since the 1970s, and also strongly disagrees with motor oil for these applications. He said he had a conversation with an engineer from CAT one time many years ago. He asked the engineer why CAT specified motor oil in hydraulics and final drives etc. at that time. The CAT engineer replied that the USA was only a portion of there market, and in the rest of the world it was often difficult to get anything but motor oil. He then went on to say - CAT sells parts! Basically inferred that yes, things won't last as long running motor oil, but its just a profit center to sell Parts. I trust our oil supplier, as he has saved me tens of thousands over the years by listening to his advice. So although I know the manual says 30 weight motor oil, I am running the equivalent weight gear oil(85 weight).
Huh? Oil is cheap, but, so am I. Entire fleet of cat excavators run 15w40 in final drives. Deere HyGard in all loader axles. 90w in all my Takeuchi and Kubota final drives. TO4 10w in all hydraulic systems.
Planetary final drives do not load gear teeth in the same way as differentials and spur gear final drives. The thought process that I was told was that the gear oil caused premature wear on the bearings and that the teeth in planetary transmissions were not loaded to the point of causing smearing or case crushing. The only thing I have directly observed is that planetary final drives will get very hot when traveling long distances. Gear oil does not transfer heat as well as engine oils do. The soft parts in units running gear oil need to be resistant to the heat issues then. As far as broken gears go, I haven't seen anything that made any quantifiable difference. If it is under warranty I ran the manufacturer's spec.
Thanks for the comments guys! Glad you made them! Did some of my own research based on the Komatsu manual and your comments. And came to the conclusion that A 30 weight oil meeting the TO-4 spec would be more appropriate than the gear oil I had put in. So we will call the first fill a flushing oil!