[Ydna]

I have a 1997 VF2 with 10krpm and gearbox option. Occasionally (every other month of so) I've heard a weird rumbling sound during power up, which *I think* happens during the low/high gearchange. It's hard to tell when the sound occurs since the power up sequence happens so fast, it's either the high gear gearchange or the Z axis homing.

The machine runs fine, it never replicates the sounds except for the power up which is what makes me wonder if it's something else (Z axis). Anyway, I climbed up onto the mill to see if there was anything obviously wrong from the outside. I noticed there's a radiator for the gearbox oil up there, with hoses leading to/from solenoids and the spindle mount.

We're going to remove the covering sheet metal this week to investigate a little further, but I wanted to post a picture of the radiator in case somebody here knows how this thing works. (I'm not familiar with the gearbox hardware). Is it normal for one side of the radiator to appear virtually empty of oil? I'm wondering if this means there's a blockage in there or something.

Thoughts?