Merc-O-Matic transmission

After letting the 53' Mercury set for about 2 weeks, when I start it up it blows trans fluid up and over the top of filler tube. By the time I get to the end of the driveway it stops. Checked the fluid with the engine running and warm after a drive and it is between the hash marks...not over filed. Does not due it with regular driveing. Cause?????????????? I know the obvious answer is to drive it more!!!!!!!!!!!!!!!!!!

 

Sounds like the converter check valve is getting stuck open. When the engine is shut down the check valve keeps the fluid in the converter. If stuck open, it will drain back into the pan and overfill it causing the fluid to gush out the filler tube. Try an complete drain and fill of the transmission and see if this cures the problem.

 

Thank you....

 

Slower startups seemed to resolve the issue. Waiting until the trans was full from the pan.