What would cause a front tranny seal to blow?

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pettybludart

pettybludart

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I had my transmission out last month and replaced the pump and also added 9 blue racing clutches.Now I,ve had this 904 worked on with lower first gear,changed out the drum,red racing racing belts,new pump and the 9 blue clutches.I,ve been racing with this tranny(904)and made about 30 passes behind the 408 in my 66 Dart.This weekend after about 5 passes,I made it too the topend of the track and noticed smoke.Well when I pulled over,there was plenty of tranny fluid leaking out.I,m assumeing it,s the front seal as the lines are all good.What would cause the seal to go so soon?Oh it,s a manual valve body also.Thanks in advance for any help.
 
There could be a grove on the shaft,or the seal was installed and someone forgot to put a little grease on the convertor snout and she burn out.That does suck.Lucky tho if she pop at say second gear shift you would of went into the wall.Glad it happened at the end.pull it out and have a good look at the input shaft after the seal is out.could also be the big pump seal.
 
daliant said:
Could be a crack in the converter snout, but hopefully its just the seal
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This was my first thought. Mopars are bad about that to begin with. Especially if the converter is furnaced braced. That ain't the best way to go.
 
Just a thought,when you pull it out measure the snout maybe your seal is too small and she got too hot and failed.
 
Tracy(Fishy68)you out there?Any ideas as to why this would happen?Too hot?I,ll be installing temp and pressure gauges now to keep my eye on it after it,s repaired.
 
Did you mess with your converter bushing? When you fire up the car, do you do so in neutral and warm up in neutral?
 
How hot was the tranny when you were making your pass? The reason why I ask is because my car did the same thing a couple of months ago when the tranny would get too hot. It would puke tranny fluid all over the road and smoke like a train. It was coming from the bellhousing area too. Once it cooled off it wouldn't leak a drop. I was running a trans cooler that was too small for my convertor. Swapped to a bigger trans cooler and never happened again. Hope this helps. Has it leaked since cooling off?

Oh yeah everyone was saying a cracked convertor with my problem too.
 
How much fluid came out? I ask because when my buddys truck blew out the conv. seal it damn near puked its guts out in seconds. when we fired it up for just a couple seconds it coated the driveway. his ended up being a plugged up vent. I would suspect it may be something simple like Badart was saying and it just got hot and spit out the vent.
 
Scott, it's possible the fluid level is too high and leaking out the vent when hot, and you may not have a problem otherwise.

It's ok to run a pint or two low on these.

Check fluid level in park and neutral, and use which ever reading is lowest.

If it's on the stick when cold (just at or below cold), you're good.

What's your fluid temp? In the traps? Cooler? Five back to back runs and the fluid will raise, if overfilled, could leak out vent.

HTH's
 
Duster346 said:
Scott, it's possible the fluid level is too high and leaking out the vent when hot, and you may not have a problem otherwise.

It's ok to run a pint or two low on these.

Check fluid level in park and neutral, and use which ever reading is lowest.

If it's on the stick when cold (just at or below cold), you're good.

What's your fluid temp? In the traps? Cooler? Five back to back runs and the fluid will raise, if overfilled, could leak out vent.

HTH's
Click to expand...
X2, I had that happen on my 330 Dodge
Kenny
 
Thanks for replys guys.I had run 4 passes allday on friday(1hr inbetween runs)then after 2 hrs decided to make a pass in the cooler night air.The car ran fine but when going through the traps noticed smoke in my rearview.This is when I shut er down and coasted.Tranny fluid was leaking pretty good out the bell housing area.The next morning I fired it up to check again(after cooling allnight)and still was leaking badly.I,ll be pulling it out again today,as the guy that built it is going on holidays next week.Will let you all know my findings.

P.S This tranny has 33 passes on it,I,m also using the biggest BeCool tranny cooler.
 
The reason I say to warm it up in neutral is that TF transmissions don't fill the converter in park. You will warm up the trans and get fluid pumping if you do so in neutral. There is a conversion that you can get installed that allows the converter to fill in park like GM trannys.
 
Thanks Redfastback,I,ll mention this to my tranny builder.The car is strictly race only for now.Thanks for the advise/ideas guys.Why does it have to be so dam hot outside when my cars break?Off to do removal in the scorching heat.Oh boy!:munky2:
 
pettybludart said:
Thanks for replys guys.I had run 4 passes allday on friday(1hr inbetween runs)then after 2 hrs decided to make a pass in the cooler night air.The car ran fine but when going through the traps noticed smoke in my rearview.This is when I shut er down and coasted.Tranny fluid was leaking pretty good out the bell housing area.The next morning I fired it up to check again(after cooling allnight)and still was leaking badly.I,ll be pulling it out again today,as the guy that built it is going on holidays next week.Will let you all know my findings.

P.S This tranny has 33 passes on it,I,m also using the biggest BeCool tranny cooler.
Click to expand...
More than likely a crack or pinhole in converter (as stated).

They'll be able to leak test to verify ..

Let us know what you find, Scott ..
 
OK I pulled the tranny,as I was unbolting I noticed a huge crack in the tranny housing.Also have cracks around the starter area.Upon removal a big chunk of the housing fell out.Too funny!LOL.Anyway,I,m thinking that when I had my rearend problems(tearing the spring perches off)the force of the rear tipping up,putting pressure on the driveshaft and the housing may have cracked it?Anyway spoke with my builder and he,s gonna check it all out and if it,s good the internals are being swapped into a spare 904 I have(from the donor 73 Dart I had)Hope it,s all ok?I know for sure we,ll be swapping out the bearings.Just glad to find the problem.Pics of the 904 housing.

PS Thanks All for the help and advise.
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Racing the 66 Dart 032.jpg


Racing the 66 Dart 036.jpg


Racing the 66 Dart 033.jpg


Racing the 66 Dart 034.jpg


Racing the 66 Dart 035.jpg
 
Wow! Damn horsepower! That might explain your problem. You are lucky the thing didn't break all of the mounts and decide to leave the car. I am sure you will get it sorted out.
 
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