My t400 trans spits fluid out the dip stick tube only while cruising on the hiway at 2000+ higher rpm. Around town stop and go driving - no leak. I have confirmed the vent is not restricted and open. It does not leak out of vent tube, only dipstick tube. Oil level is fine....actually a pint low. What do you think the issue is? pump halves not flat or distorted? fwd drum checkball leaking? sealing ring leakage? Other?
Well, I checked the lines for blockage...they were clear. Only other possibility is something internal. I pulled the trans today. We will see what the rebuild shop says.