Phantom Trans Leak?

[Bruzilla]

We installed the new 727 into the Roadrunner on Sunday, and I fired up the engine and backed the car down the driveway and drove it back up to make sure everything was working, and all felt fine. I was too damn tired to crawl underneath and look at things though.

Yesterday I looked under the car and saw quite a bit of fluid under the trans. We spilled quite a bit when we removed the old one, but I thought most of that was dried up by now and this stuff looked fresh.

I jacked the rear-driver's tire up about .5" off the ground, started the car, put it in Drive, and looked for leaks but saw nothing. The car was "moving" at about 20 MPH, which was a lot faster than it was going when I was moving it up and down the driveway, but there was nothing leaking out. I let the car run like that for 20 minutes to give everything a chance to heat up and still nothing. Then I shut it down and watched for another 20 minutes and nothing.

So is there is there something that could have been leaking and has now stopped? I put a new O ring on the dipstick tube and was wondering if maybe the fluid had been leaking from there and stopped once the O ring swelled a bit.

 

[1967coronet440]

There was a thread not long ago about a very similar problem, I believe the concensus was fluid draining back from the cooler... I'll see if I can find it

 

[Bruzilla]

There was a thread not long ago about a very similar problem, I believe the concensus was fluid draining back from the cooler... I'll see if I can find it

That was the first thing I suspected. I had a 72 Roadrunner that I bought from an Aamco Transmission shop back in 85. Some sailor had brought the car to them for a trans rebuild, couldn't pay the $900 bill, and signed the title over to them. I drove the car for a couple of weeks, and then the trans failed. Turned out the Aamco guys hadn't tightened up the coolant lines and most of the fluid had drained out. So I'm pretty obsessed with making sure those lines are on there right and tight, and there's no sign of leakage there.

 

[69 GTX]

Richard Cranium this is your cue!!!

 

[Car Nut]

Selector shaft seal

 

[PurpleBeeper]

First, transmission fluid doesn't "dry up", so maybe what's on your driveway is from the trans. swap. How much trans fluid did you put in? Maybe just check the fluid level again? Is it low?

 

[Bruzilla]

First, transmission fluid doesn't "dry up", so maybe what's on your driveway is from the trans. swap. How much trans fluid did you put in? Maybe just check the fluid level again? Is it low?

Sure it does. Takes a while, but it goes from wet, to dark, to gone over time.

 

[LemonWedge]

727's are notorious for leaking out of the case vent into the bell housing area. If it's coming from the bell housing, it could be the pump seal, but it's likely the vent puking. They make a kit to move the vent to the rear of the case, but you've got to disassemble the transmission to do this.

 

[727]

If the torque converter was filled before it was installed, maybe it leaked ATF into the bottom of the bell housing(not really a bell housing)when sliding it into place . Windage from the vert blew the puddled fluid out on the first ride.

 

[PurpleBeeper]

Sure it does. Takes a while, but it goes from wet, to dark, to gone over time.

You mean "soaks into the concrete", don't you? It's basically mineral oil. How long does baby oil take to "dry up"?" Try it, what the heck.

 

[eagleone1983]

Bru, don't even bother. I've given up on mine and put an old cookie sheet under it. I've tried replacing the dipstick tube O-ring, new pan, the new style pan gasket, and checked the gear selector for wetness. Screw it, keeping a quart of trans fluid around to refill every once in a while is way less of a headache.

 

[Daves69]

Do you have a general location to suspect?
I'm thinking like front, mid, and rear of trans.

 

[AR67GTX]

Lots of leakage possibilities - front pump, front seal, dipstick tube, assembly pin for rear servo that is exposed at rear of case, I think there are two seals on the selector/kickdown shaft assembly, coolant lines, pressure port plugs, pan gasket, and speedometer adaptor. You may have to wash it down and dust it with talcum powder to pin down where the leak is starting from.

 

[beanhead]

Could it have possibly just leaked out enough fluid to get below the level of the leak? Maybe get it nice and full and then see if it leaks again

 

[furryfrog]

I know when I lift the front of my car up, I leak tranny fluid out the rear seal on my 727. I'm sure the bushing and seal are worn though, still on the to do list to repair.

 

[MarPar]

 

[Malicious]

The thread earlier was probably mine:
http://forbbodiesonly.com/moparforum/threads/converter-drain-back-727-leak.124490/

I've got the recommended dipstick and have installed a one way valve in the coolent lines, I'm looking to install the dipstick some time soon topp up and then take it for a test soon. The weather has just turned sour here, so its a matter of getting a good day to do it.

 

[dvw]

Either it spilled or there really is a leak. Trans seals don't swell. Trans fluid does not evaporate. If it sits long enough the converter will drain back. The fluid level will rise and uncover nearly every posible leak path. Throttle pressure shaft seal, shift shaft seal, line fittings ,lines themselves, nuetral switch, low band pin (bottom of the tail shaft to case), pressure tap plugs, tail shaft gasket, snap ring access gasket (under the trans mount), speedo adapter oring, speedo gear seal, yoke seal. These can all be replaced in the car. Pump gasket, oring, pump seal, converter, plugged vent all require removal. Clean it up, dust with powder. The fluid will wick darkening the powder. Then repair as necesary. With the exception of front pump weepage the rest of the leaks are pretty easily repaired.
Doug

 

[khryslerkid]

My 2003 Dodge Ram likes to drain back and it overflows the dip stick tube. I leave the level one pint low and don't have a problem anymore. I'll start it in neutral also if it has been sitting for awhile.

See if the outside of your dip stick tube is wet and check at the base of it.

 

[ctreser]

Mine has had drain back ever sense I replaced my valve body. Leaks out the vent a little after sitting a little while. Also have to run it in neutral before using reverse. I put up with it though.