Leaking 904 Transmission.

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lsrguy2007

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I bought a 1973 Dodge Dart Sport about 9 months as ago. The transmission started leaking just drops of fluid a few months ago. It's progressively gotten worse over the last few months. It seems to leak more when sitting than it does when driving. I stopped to get gas the other day and cleaned off the windshield and also waited a while before driving away. I'm that time I looked under the car and saw no leaks. I've searched this site and found some posts talking about leaks but nothing about my same situation. Do does anyone have any idea what I should look for? Any help is appreciated.
 
Yes, jack it up, put it on stands and actually go under there with a flash light and look.

RRR- another crystal baller here.

You need to actually put in the work to own one of these cars. Not everything is solved thru the internet. Gaskets fail some times over night. These cars leak, it’s 50year old technology.
Syleng1
 
Syleng1 said:
Yes, jack it up, put it on stands and actually go under there with a flash light and look.

RRR- another crystal baller here.

You need to actually put in the work to own one of these cars. Not everything is solved thru the internet. Gaskets fail some times over night. These cars leak, it’s 50year old technology.
Syleng1
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I needed someone to tell me that. I sold my floor jack and jack stands before I bought the Dart. Thanks.
 
My 67 dart 904 leaked like a sieve.

I replaced:
  1. Rear yoke seal
  2. Speedometer gear holder seals
  3. Teams pan seal
That cleared up 90% of the leaks.

Other points of leaks:

  1. Front trans oil pump to housing seals
  2. Front torque converter seal
 
besides dana's excellent list of the usual suspects, another offender is the shifter shaft seal-- where the rods hook up to the controls for valve body. a little more involved, but if you're doing a pan seal, it's really not all that much more work.
 
Syleng1 said:
Yes, jack it up, put it on stands and actually go under there with a flash light and look.

RRR- another crystal baller here.

You need to actually put in the work to own one of these cars. Not everything is solved thru the internet. Gaskets fail some times over night. These cars leak, it’s 50year old technology.
Syleng1
Click to expand...
On second thought I'm 70 years old and have a bad back. To say if you own one of the older cars you should be willing to crawl underneath it and troubleshoot it is ridiculous. I'm trying to get an idea what the problem is so I can get a feel what it would cost to fix. Im retired and on fixed income. Also my if there's anyone in th St. Louis Missouri area that can help work on it Id appreciate it.
 
trying to get an idea of what could potentially be wrong with it and only having the diagnosis of: it leaks more when parked, without any further investigation is an exercise in futility.

it literally could be anything from loose pan bolts to a hairline crack in the case.

asking what something would or should cost to fix on an internet forum is just setting yourself up for a whole slew of remarks and discussion that is going to be more noise than information.
 
I would go to the parts store and get a bottle of dye. Put it in and go to a local shop to see what they can find. Ron Hendrixson in St. Louis. Tell him his old gateway tech guy not named Al sent you. Mark 1 Auto service Center. 314-843-6644. Open from 9-7.
 
rbkt65 said:
I would go to the parts store and get a bottle of dye. Put it in and go to a local shop to see what they can find. Ron Hendrixson in St. Louis. Tell him his old gateway tech guy not named Al sent you. Mark 1 Auto service Center. 314-843-6644. Open from 9-7.
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Thanks for the information. I'll look Ron up.
 
junkyardhero said:
trying to get an idea of what could potentially be wrong with it and only having the diagnosis of: it leaks more when parked, without any further investigation is an exercise in futility.

it literally could be anything from loose pan bolts to a hairline crack in the case.

asking what something would or should cost to fix on an internet forum is just setting yourself up for a whole slew of remarks and discussion that is going to be more noise than information.
Click to expand...
Ok. I agree. Thanks.
 
rbkt65 said:
I would go to the parts store and get a bottle of dye. Put it in and go to a local shop to see what they can find. Ron Hendrixson in St. Louis. Tell him his old gateway tech guy not named Al sent you. Mark 1 Auto service Center. 314-843-6644. Open from 9-7.
Click to expand...
It looks like Mark 1 is permanently closed. I'll try to find Ron.
 
lsrguy2007 said:
It looks like Mark 1 is permanently closed. I'll try to find Ron.
Click to expand...

Typically this would be cause for a removal of the trans and re seal, unless it’s just the pan gasket.
Most shops won’t do just one leak, because it could come back in a week with another one.

“I just paid to have my leak fixed and it’s leaking again”

I’m sure you could see that happening.

It’s called an R&R and reaseal.
They take the trans out and replace all the seals, and usually the pump and tailshaft bushings as well.

But maybe yours is just a pan gasket.
 
lsrguy2007 said:
On second thought I'm 70 years old and have a bad back. To say if you own one of the older cars you should be willing to crawl underneath it and troubleshoot it is ridiculous. I'm trying to get an idea what the problem is so I can get a feel what it would cost to fix. Im retired and on fixed income. Also my if there's anyone in th St. Louis Missouri area that can help work on it Id appreciate it.
Click to expand...
Big time red x candidate post! Maintenance and car ownership are like fries and ketchup,
More so with an older car. Sounds like this guy thinks it is still 1974 and his car just rolled off the lot
 
TrailBeast said:
Typically this would be cause for a removal of the trans and re seal, unless it’s just the pan gasket.
Most shops won’t do just one leak, because it could come back in a week with another one.

“I just paid to have my leak fixed and it’s leaking again”

I’m sure you could see that happening.

It’s called an R&R and reaseal.
They take the trans out and replace all the seals, and usually the pump and tailshaft bushings as well.

But maybe yours is just a pan gasket.
Click to expand...
Ok. Thanks for the information. We're going to put it up on a rack Wednesday and look around a bit.
 
I wouldn't call the situation normal but it happens often when sitting for a while. The torque converter drains down and virtually "overfills" the transmission.
 
We put it up on a rack and there's a vertical plate at the front of the transmission. We loosened the two bolts we could reach and some transmission fluid leaked out so I'm thinking the front seal is bad. I found a guy in St. Louis that works on these older transmissions. He wants $500-600 to replace all of the outer seals. He also talked about just rebuilding the transmission but at only 66K original miles I'm not sure it needs it. Anyone have any thoughts on the price to replace the seals and also the need for a rebuild? Thanks in advance.
 
Does his quote include removing and replacing the transmission? If so. I suppose that is not too bad. I pulled mine 4 or 5 times one year and was about to pay someone, lol.

It could very well be the pump seal. Here's another thread that covers leaking in front.
A-904 Pump front seal replacement.
 
66fyssh said:
Does his quote include removing and replacing the transmission? If so. I suppose that is not too bad. I pulled mine 4 or 5 times one year and was about to pay someone, lol.

It could very well be the pump seal. Here's another thread that covers leaking in front.
A-904 Pump front seal replacement.
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Yes, it includes removing it from the car and putting it back in. Thanks for the info and the link.
 
lsrguy2007 said:
Yes, it includes removing it from the car and putting it back in. Thanks for the info and the link.
Click to expand...

That's a great price then.

Then comes the question about total rebuild. If you have the funds, now would be the best time. If you don't know the background on the trans, it would be a good idea. But, it won't be cheap, but these trans are pretty tough so... hard decision!!!
 
I was quoted 1200 if I hand them the trans to have it rebuilt.

500 to pull and reseal seems like a good deal I would suspect they can look over the internals at the same time and might agree rebuild now not needed, or they might find all kinds of issues.
 
Dana67Dart said:
I was quoted 1200 if I hand them the trans to have it rebuilt.

500 to pull and reseal seems like a good deal I would suspect they can look over the internals at the same time and might agree rebuild now not needed, or they might find all kinds of issues.
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Ok. Thanks for your input.
 
I don’t know how much you want to save,,,,but this stuff is worth a try .
I’ve used it in newer model cars,,,and it truly works .
It cost about 12 dollars a can,,,,but it might help you .

I’ve used it and can vouch for its effectiveness .
I know it doesn’t state anything about helping seals,,,,but it also helps with those too .

I’ve used it in my automatic transmission and power steering.
It made the steering quit leaking at the rack,,,,,and the transmission shifts like new again.
The modern transmissions have many electric and pneumatic valves,,,,,man after about 10 miles I could tell a difference.
My daily is a 2000 model,,,with over 400,000 miles on it,,,,made all the difference in the world .
You might consider a can ?

Tommy

IMG_5278.jpeg
 
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