I am working on a Bally Skill Derby and I took the gear box for the forward/reverse motors apart and the gear oil was low and dirty. I cleaned everything and didn’t know what kind of oil to put back in. I asked around and someone recommended to use regular Mobil one 10W - 30. I put that in and turned the gears. There was resistance which I believe would be normal, but I don’t know how it should feel. The original oil had less resistance but it also had less oil from a leak. I then bought Mobil one 5W - 20 and that had less resistance. That is what is in the case now. I saw that Mobil had a gear oil but the viscosity was way higher. My concern on putting in a thicker oil is that the resistance would be too much for the motor and burn it out. I would like to put this machine back together but I need some advice on what oil to use. Once everything is back together, it is impossible to change the oil without taking it all apart. So the question is, what kind of oil should I use to replace the 1960 oil in my gearbox?

Thanks,

Larry.

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Thanks for the reply.

In the one picture you can see the gear case is upside down. This is because I could only work on this area upside down. If you look at the case, there is a screw that can be removed for adding oil. That screw normally will be facing up. Also, this gear box has two gaskets to keep the oil from leaking out. It should be filled up to the screw level with oil.

The back door, of this unit, has a cam that uses a different gear box. It is a thin riveted box. I took one of these style gear boxes apart in a Bally bowler and it was just plastic gears and old grease.

The gear box I’m wondering about is oil filled.

I will also take the other thin gearbox apart to inspect the gears. That’s the next section to be done. I will probably use Superlube grease on those gears.

Sorry. I didn’t show the cases fill screw. Here’s more pictures.

The two motor rotors have oil ports for their brass bushings. I used 3 in1 oil in there. The gear box has its own oil that is different than the 3 in1 oil.

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Hi Mitch,

Same gearbox. If it was to have grease, wouldn’t there be a Zerk fitting? How would the grease get to the gears? The grease would be hard to get in the threaded hole and would fall to the bottom or stick to the sides. Not like a bearing where it is shot into the balls. I still think it has to be liquid.

I’m not either. I can’t see oil just because I don’t believe it needs an oil bath. The gaskets made me think that oil was correct, but I don’t know. Thanks for the info. The bingo page is really informative.

There was some info on this site about a Bally Big Show and there was a debate about liquid oil or grease. Either one seemed to work, but if you used oil, you would have leakage through the shaft. I think I’ll go to grease. I have a tub of Superlube teflon grease. Thanks for the input.