904 Transmission Leak

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Walker434

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I'm getting my street/strip 71 Dart back on the road and ready to compete in Drag week this year for the 4th year in a row. I didn't think the car was leaking any fluids... first few test drives and the underneath was spotless.

The car sat in my car port for 4 days then I noticed a puddle underneath. With the car on jack stands I cleaned all the fluid up and off the pan. Took it for a drive.... got back and no leaks. Again the car sits for 3 or 4 days before it starts leaking again. Strange how it doesn't seem to leak while driving but after sitting for a few days. Anyone else experience this?

Dart 1.jpg
 
The first step is to locate the area it is leaking from.

Speedometer pinion? Pan? Rear seal? Dipstick O-ring? Vent? Front seal? Converter drain plug? Or?
 
The first step is to locate the area it is leaking from.

Speedometer pinion? Pan? Rear seal? Dipstick O-ring? Vent? Front seal? Converter drain plug? Or?
I'm not really sure yet. Going to get it back in the air tonight and look. It appears to be the pan but I thought it was strange that it starts to leak after sitting a few days.
 
Clean it again when it is safely in the air.

The leak may be slow and not become noticeable for a few days.

So clean it and let air dry. Then with a new, dry natural animal hair paint brush, dip it in talcum powder and coat any possible offending areas. Apply the powder liberally. That will 'clot' at the leak source first, but be ready to check it as often as possible.
 
A lot of places to leak above the pan rail. Automatic dishwasher soap diluted in a spray bottle will clean things up. Flashlight and white paper towels dabbing prone areas looking for red fluid. Start high and work your way down. As the trans sits more fluid drops into the pan raising the fluid level until the next start.
 
I had a tailshaft seal do that. Only dripped when sitting. Polished up the yoke and replced seal. But as said. Find it 1st.
 
Somebody needs to invent a magic code reader that plugs into the car and tells you exactly where the transmission is leaking..
 
I would check the pan & pan bolts, especially if it has a sheet metal pan. Mine developed a leak very nearly the same & I had a time trying to find it. I finally took the pan off & it was cracked around two of the bolt holes causing it to leak. I replaced the sheet metal pan with a deep cast aluminum pan & "voila", no more leaks. I've had this same pan on for ten years & have only removed it twice to check adjustments & change the fluid & filter.
 
Shift shaft seal is real common on those. Torque converter drains back after sitting raising the fluid level up to the shift shaft seal. (the large one) they get old and hard and cracked.

I have changed those with the trans in the car before. Had to tap a scratch awl into the seal tin edge then screw a sheet metal screw into the tin of the seal and pry it up out of there.

Made a little tool for pressing them back in again with a large c-clamp.

Believe 904 and 727 use the same seal, same valve bodies. Can pump your fluid level down by pulling l the cooler lines at the radiator and run it for 20 seconds and pump a gallon into a drain jug for reuse. 2 rubber lines on the ends of the cooler lines into your reuse jug saves spraying oil everywhere.

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Chrysler makes a seal tool too. Did not like the way the remover worked, so just used a sheet screw for seal removal.

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I believe George nailed it! I replaced a shifter shaft seal in the car one time also. I rolled the dice and just jacked it way up on the drivers side, so the fluid would run away from the seal. I was lucky enough to pry the old seal out with a small flat screwdriver. I put the new one in with an appropriate sized socket and a big C clamp.
 
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