Has anyone here ever found it necessary to block the vent on the front pump in a 904 and move the vent to the tail shaft? THe rebuilt transmission in my brother's van leaks out of the inspection plate when the motor is running. This weekend we are replacing what should already be a new front pump seal. The torque converter is also new. I am considering blocking the stock vent and moving it to the tailshaft and was interested if anyone had any input about this.

Thanks.

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Casually looking for a Clifford hyperpak intake for cheap.

Re-engineering like this is almost never necessary or wise. Finding and fixing the problem will be the wiser course of action.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I agree. I just was hoping to kill two birds with one stone while I had the transmission separated from the engine. it probably is just the pump seal anyway since I installed a Transgo TF SC kit in the transmission and the TF SC kit is supposed to stop the "burping" out the vent that happens sometimes on torqueflites (so I hear). I suppose the upside is that I am getting REALLY good at pulling transmissions on Dodge vans.

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Casually looking for a Clifford hyperpak intake for cheap.

Is the trans getting too hot by any chance? I had a kinked cooler line once and the trans burped as a result.

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Joshua

The amount of clearance between the front pump bushing and TC hub is important in controlling the amount of ATF hitting the back-side of the front seal, and the seals ability to contol the oil.

Excess clearance allows more oil volume then the drain back passageway can handle. Inspect the TC hub for wear & scoring. Replace / repair if needed.
Change the front pump bushing and chamfer the end of the drainback hole, to allow any oil getting pass, to quickly return to the pan.
DD

Thanks for the tidbit, Doug! I've never thought of doing that and will work it into future builds...

Lou

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Home of Slant6-powered fun machines since 1988

Hmmmm. Thanks! I will check all these things out this weekend. I really want to be done pulling transmissions off of this van.

The transmission starts leaking as soon as the motor is started, so I don't think it is a heat related issue. The cooling lines are straight (except for the factory bends).

The torque converter was purchased new last year, but I will inspect the hub surface for wear or rough spots.

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Casually looking for a Clifford hyperpak intake for cheap.

The Pro Trans in my race car came with the vent moved to the tailshaft. It seems to work fine but the tunnel in my early A body is so tight that I had to punch a hole in the floor and put the vent inside the car with a hose.

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If you didn't drive it there, it's not a street car.

had an A727 that the pressure was turned to high on valvebody...it leaked out vent..... just another place to look

Hmmm, good suggestion. The shift kit had me turn the line pressure way out. I might turn it in a bit before I pull the whole tranny.

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Casually looking for a Clifford hyperpak intake for cheap.

Doc gets the cigar this time. Pulled the transmission and took a look at the bits on the front end. Torque converter hub looked fine, no crack in the corners of the tang slots. Seal was in good shape, no tears, rips, or worn spots, vent at the top was dry as a bone. Then I noticed some seepage from between the input shaft and the reactor shaft. I wiggled the input shaft and was stunned to find about 3/8 inch side to side play!

Fortunately, I had ordered a new pump bushing. Even more fortunate, I had a spare rebuilt front pump!

So we swapped the rebuilt front pump and, buttoned it all back up, and took it for a test drive. No leaks! Yay!

Thanks for the help guys, I couldn't do this without you all.

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Casually looking for a Clifford hyperpak intake for cheap.