- Moderator
- #21
Commonly the gunk that builds up, be it varnish or sediment from the clutches wearing get loosened up by the fresh oil, then plug up the valve body, which lowers the pressure to hold the clutches, resulting in slippage, and imminent failure of the trans. As stated, if the fluid is black and acrid smelling, don't waste the money on the oil change, as it is already too late. Dark brown shows neglect, as it is old fluid, but isn't a guarantee of trouble, as long as it has some red tint to it. Milky or dark brown with no red at all, not so good.
