Reply To: Sticky Blue Grease in 1908 Transmission?

[Luke Dwyer]

Having owned a few brass cars, my opinion:

First is that whatever that blue stuff is is probably an arbitrary lubricant that someone added over the last 100 years and is very unlikely to be what was used originally. So, I think there’s nothing magical about whatever that stuff is. And remember that we understated lubrication technology a lot better than they did 100 years ago, even a generation ago. Whatever it says in the owner’s manual might have been good for the time but I think we understand things a bit better today.

Second is that whatever you put in needs to primarily lubricate the bearings which hold the gear shafts. And whatever that is will take care of the gear teeth as they mesh. Hence grease or something super thick could starve the bearings and lead to a failure although it may lubricate the teeth.

I’ve used steam cylinder oil, a product called Shell Valvada 680. There are varying thicknesses of steam cylinder oil, but the 680 stuff approximates 600W gear oil. But again, you’ve got to lubricate the bearings and bushings which support the gear shafts. In cold weather I’ve found that the 600-W stuff gets too thick.

So an alternative is to use a modern 85w-90 gear oil but one that does not harm brass or bronze bushings, a GL-4. I’ve used Sta-Lube brand, but whatever make sure it’s GL-4 or earlier (lower number). If that’s too thin, which it probably will be, you can add Lucas Oil Stabilizer which thickens the mixture yet is supposed to still be not harmful to yellow metals. Or you can mix it with steam cylinder oil to get something which will allow smooth shifts yet still be thin enough to lubricate bearings and bushings.

As I see it, the only disadvantage to thin gear oils is that you may experience hard shifting if you don’t have the technique down well to shift at exactly the right time, and second the transmission will probably leak unless you have installed modern seals. But a leaking transmission or differential is preferable to inadequate lubrication inside.