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TH400 Pushing fluid out the vent

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27K views 18 replies 9 participants last post by  Toro Toro  
#1 ·
What could be causing my TH400 with a RMVB and a brake to push fluid out the vent tube after a couple passes. I have a Durale cooler with fan running all the time.
 
#6 · (Edited)
I've had this trans gone thru three different times by different builders and its always the same story. I made 2 passes about 45 mins apart last night and it pushed about 4 oz out. I kept the trans cooler fan running between passes also. I cant believe its heat related.
I have a Lokar dip stick adjusted to keep the fluid level even with the top of the pan.
 
#13 ·
Some ancient history. Years back I got to tour the B&M shop as it was in the 60's, before they 'upgraded' in the 90's. Had some extremely interesting parts on the archive shelf. There was converter setup that featured a movable turbine via a pedal, like fore and aft to change stall while in the car. Mr. Spar told me it did some strange shit in action, worked like this, pedal in moved the turbine away, from the stator/impeller, sucked the turbine IN, if I recall, whatever it didn't work like they figured.
Tons more interesting shit there, but I digress;
Back in the day, late 60's before Lenco, fuel dragsters and floppers used the same trans as the engine, GM/400, Ford/C-6 and Mopar/Torqueflite.
I was told they routinely used pressures over 300 to keep them alive. Nothing new under the sun.
 
#14 ·
What dipstick are you running?

I have noticed a strange issue with my 400 running the Locar dipstick/tube. If I leave it in I get fluid in my catch tank. If i keep it out, nada.

When I start the car cold, and warm it up, once I shut the engine off air pressure with a fine oil mist is coming out of the vent hose if the locar dipstick is in place, it has 2 orings and is sealed good.

Cold warm up with the dipstick out, nothing happens. I take this as a single -3 hose going from the vent to a tank is just not enough. I'm making an adapter to go in the dipstick tube and hook it to the vent/catch tank.
 
#17 ·
Thanks "Honk" for the sound advice. I made 3 passes last night and it pushed fluid out each time. I pulled the dip stick out about a 1/4 inch and made 3 more passes and the catch tank was dry.
Did you finish your vent modification to the dip stick? Any pictures or more info?
Thanks again.