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39 Dodge Gearbox oil very foamy?

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Just drained my 39 Dodge stock gearbox as it crunches when going into 2nd both ways when cold, its better when it heats up so I thought I would look at the oil first and then add an additive to see if it helps.

I ran the car on blocks for 5 or more minutes then drained. The oil came out very foamy, 30 minutes later the bucket of oil is still very foamy? Oil looks clean.

I was going to reuse the oil but the foaming is something I've never experienced so maybe I should use new oil.

What would you do?

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Use new oil. The foamy oil is probably contaminated with something. Maybe water.


If I had synchronizers not working I would change the oil anyway, and see if it helps. Otherwise you would be tearing the transmission down to replace the synchronizers. Use some synchronizer friendly oil, NOT hypoid oil for a rear axle. I don't know what might be available to you in NZ. I am using Redline synthetic 75W140*NS* in my 1936 Pontiac transmission, works good. 


In a synchronized transmission something closer to plain oil is preferable to the super-slippery type used in a rear axle. If cheaper and more common is what you want, maybe GL-1 gear oil or some tractor oil would be good.


Before putting too much thought into the oil as a cause of the grinding, make sure your clutch isn't dragging.


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