Originally Posted by
Jetfixer
I bought my filter from you, Ron! My educated guess would be that since air can be compressed, the venting process done by BUDS is intended to prevent abnormal pressures building up within the valve body of the HCM and then getting "slugged" out, possibly causing either damage or accelerated wear on the HCM components. Also, compressed air in any hydraulic system can cause "foaming" of the fluid (oil in this case), which can continue through the hydraulic passages of the valve body until it gets back to one of the oil sumps to settle out. Personally, I don't leave air in brake or clutch systems, why leave it in an automatic transmission system?