Hey fellas, got an A904 in my 73 Dart Sport 340. Planning to rebuild it in a week or so, but, it has an issue that is a bit odd to me.

I top it off with fluid, drive it and all is fine. If I let it sit over night, no problem. However, if it sits for 24 hours or more, it leaks about 2 quarts onto the floor.

My guess is that the converter is draining back down to the input shaft and thats where the trans fluid is coming from. but, if thats what it is, how do I stop it?

Next question, Im ordering the parts to rebuild it. Anyone have any input on what converter and what trans kit to order. I dont plan to run a high stall converter or anything since its just a mild cruiser.

Laine.

Drainback is normal the leak is not. Fix the leak which is probably the dipstick tube seal. If you lose 2 qts I think you are over filling it to begin with. Are you checking it running in neutral.

clean it off with the car wash wand then the next day see specifically where it is leaking from. Sprinkling talcum power on it can help pinpoint a leak as they can be deceptive. I think there's 4 or 5 locations where it could be leaking from but not from the input shaft (front pump seal) when it ain't running since the fluid level ain't that high. Transgo TF1 shift kit & Transgo used to offer a converter that was a bit more tight than stock (more efficient) for a daily driver & no doubt converter tech has improved in 40 yrs if a tighter converter is what you are after. (it does have a 340 but you did say mild cruising )

Also if you use a Transgo shift improver kit, they are supplied with a new manual valve which eliminates drainback.

When they leak like that it can also be the shift shaft seal.

2 quarts is a ton of trans oil. It must look like they beached the Exxon Valdez at your place.

Nothing can eliminate converter drainback, the Transgo valve merely allows the converter to recharge in Park.

I think you may have the modified manual valve supplied with the Transgo kits confused. That valve allows the convertor to fill in the park position as well as neutral. Sonnax offers a similar manual valve to do the same thing as well as a new pressure regulator valve that fills the convertor better at low engine speeds.

I 2nd

When they leak like that it can also be the shift shaft seal.

I wiped it down and put the car up on stands for the next couple weeks while Im out of town. When I get back, I should be able to pin point the offending seal/gasket.

And to answer, yes, I checked the level and filled it properly.

I'll be rebuilding the 904 I have sitting in the shop and replacing the trans in the car, so the leak may be a moot point anyway.

Laine.

Either way, end result is I can drive the thing from Alabama to Nebraska (moving). Saves me at least one trip with the trailer.

Its pretty cool having a "collection" of Mopars, until you have to move 1100 miles. Becomes quite a logistical nightmare at times.

Laine.