atf or gear oil

[Pu241]

but I was under the impresion that gear lube 80w90 is equal as 30w? I think I read ot some where

Don't think so, put a little of gearlube (80w-90) side by side with 30W and let us know if you think they have the same viscosity.

[bravekozak]

I used to test oil viscosities in a lab. The preferred method was to select the properly sized viscosity tube and suck the oil into the tube with a small vacuum pump. I then capped it and set it in an oil bath at 100F an let it come to temperature. Later, I removed the rubber cap and lowered the oil to the starting line with my finger. I simultaneously removed my finger and started the dual timer. I pushed the button again at the middle line. The first timer stopped and the second timer started. I stopped the second timer fluid passed the third line. I then multiplied the time by the calibration factor for each bulb to determine the average S.U.S. viscosity.
Yes, I also tested my car oil at two different temperatures.