Pump Oil

[Bradf]

Anyone have a special preference when it comes to the type of oil they use in their pump?

[SmokinLowriderSS]

I have the remains of a 5-gal bucket of Mystic JT-8 premium 85w-140 from changing the fluids in my 4x4 truck/man tranny/x-fer case. works great in my Berk "F". Proabaly 3 years worth.

[HammerDown]

Anyone have a special preference when it comes to the type of oil they use in their pump?
No gears in there...just 2 bushings and the shaft. I use straight 50 wt motor oil or the bottom of the barrel gear oil and flush it every few trips out.

[wrenchdaddy]

I have two sets of bearings in my panther pump and I use royal purple 75w-90

[Gearhead]

As Hammerdown related, there are no gears in the rear of the pump, so a "rear end EP gear oil" should not be needed. Secondly, the pump never sees any heat and stays quite cool.... watercooled. Therefore a light weight mineral, hydraulic or motor oil should be sufficient. A 90 weight gear oil viscosity wise is the same basic weight as a 40 to 45 weight motor oil. A 140 gear oil is similar viscosity to 70 motor oil and is quite heavy.
I don't know what the factory fill was, but if I remember correctly it sure seemed light. I have used many oils over the years, but last year I tried a 5w30 synthetic motor oil and I pulled the pump down this week to change impellers and all looked fine. Also think that some of the pump manufacturers just have water running by the bushings and water is pretty thin!
What do you pump manufacturers think?