Trans leaking out of tail shaft.

[Street fighter]

I have a 73 charger with a 727 trans and it have a leak at the tail of it, no leaks anywhere else it have been doing it for about a year.it leaks going down the road and sitting still over night.I have checked all over it and can't find any out side leaks,what can cause this ? I am going to remove the trans than the tail shaft housing and tilt it down hill and see if I fine the leak.The tail shaft housing can't be removed without a lot of troubles under the car.Do anyone have any ideals what could cause this leak.Its not over filled with trans fuild. it's a tci trans with low milage.

 

[66Satellite47]

Could you give a more precise location of where you see the leak?

 

[Fran Blacker]

Drive shaft trans seal, tail shaft bearing gasket, speedo gear o-ring and gasket tail shaft to main trans housing. Worn tail shaft bushing maybe.

 

[AR67GTX]

If it's truly at the very tail then it would almost have to be the rear seal at the sliding yoke. But as others have said I would look further ahead and make sure it's not further towards the front and flowing back to the tail on the exterior. Replacing a rear tail housing seal is an easy job - pull the driveshaft and yoke out, pry old seal out and drive new seal in - being careful to seat it squarely. At the same time it's a good idea to inspect the rear bushing and the yoke for excess wear.

Also, it's not a terrible job to pull the whole tail housing. You have to pull the rear mount and support the transmission with a jack. The bolts holding the tail housing need to be removed. Then there's a little plate on the bottom near the mount, secured with two screw that has to be removed to spread a clip apart to free up the tail housing from the output shaft/bearing so it can be removed - after removing the speedo cable, etc.

 

[MiradaMegaCab]

Could be the slip yokes metal plug popped out, letting fluid past the splines.....

 

[493 Mike]

Another possibility is use of an old slip yoke with a vent hole in the center and no spline seal installed.
Mike

 

[oldbee]

Besides all the answers it could be leaking at low-rev anchor pin. Lower left edge where tail hsg & main body mate up.

 

[Street fighter]

If it's truly at the very tail then it would almost have to be the rear seal at the sliding yoke. But as others have said I would look further ahead and make sure it's not further towards the front and flowing back to the tail on the exterior. Replacing a rear tail housing seal is an easy job - pull the driveshaft and yoke out, pry old seal out and drive new seal in - being careful to seat it squarely. At the same time it's a good idea to inspect the rear bushing and the yoke for excess wear.

Also, it's not a terrible job to pull the whole tail housing. You have to pull the rear mount and support the transmission with a jack. The bolts holding the tail housing need to be removed. Then there's a little plate on the bottom near the mount, secured with two screw that has to be removed to spread a clip apart to free up the tail housing from the output shaft/bearing so it can be removed - after removing the speedo cable, etc.

Besides all the answers it could be leaking at low-rev anchor pin. Lower left edge where tail hsg & main body mate up.

I have already replaced the tail housing seal twice and the tail housing bushing .You can see trans fluid on the rear of the tail housing and the speedo I will try removing the speedo gear and install a new oring. The tail housing on my 73 charger will not come off the trans with the trans in the car because of the strut rods and the trans mount support , the rods runs through the trans support. I have pulled the tail before but I have never been able to get it out because of the small opening at the rear, maybe I am missing something I have also replaced the yoke will try again thanks.

 

[Street fighter]

Could you give a more precise location of where you see the leak?

The fluid is at the tail of the trans right where the yoke goes into the rear seal of the trans. every where else on the trans is clean,new yoke,driveshaft and bushing in tail housing.

 

[miller]

trans is clean,new yoke,driveshaft and bushing in tail housing.

You say the bushing, and seal have been replaced at least once. And, still leaks...something doesn't sound right. How much up and down play is there, at the rear bushing? If too much, yeah, the yoke shaft will 'wobble', making the seal there useless.

Without seeing it, have to guess, either a wrong part, or something on the tail housing is bad. When changing parts, did you see any damage?

 

[mopar 3 B]

I have seen the yoke itself leak on that year of driveshaft. Rightout the back side of the yoke. Before proceeding to far is the transmission vent functional?
There is nothing in the 727 that pumps fluid back that far. Acceleration forcing fluid past the tailshaft bearing and splash lubricates the bushing and seal.
Someone going to tell me I am full of bs i can feel it.

 

[miller]

Someone going to tell me I am full of bs i can feel it.

Nope. I'm not! The 'new' slip yoke I bought for mine, was slightly undersize, but still sealed up.

Pretty simple stuff, but simple things can easily be over-looked, and make problems.
Like...drain-back port blocked off? Pretty sure, off top of my head (lol), there's one.
Seal actually fit the shaft enough to seal?
How about stand back, and throw some common sense at it!

 

[Steve Garner]

We tend to focus our attention where we see the drip. You have to remember that everything gets blown to the rear and it finally drips off at the end. Oil will run along the pan rails then down the rear housing to the area around the speedo. If you say it's also wet around the speedo housing that's a good sign that it is further forward. Leaks will seldom migrate forward. I would take a good quality brake cleaner and an air hose under there and clean and dry everything. Go for a short drive and get under it right away and look for the slightest damp spot. If you don't see anything just let it sit and look under it periodically. If you see a drip start after sitting, follow it back. Things like the dipstick tube and valve body shaft seals usually only leak when the trans sits and the convertor drains down, raising the fluid level in the trans above those seals. If nothing develops sitting you now have a good idea where to look, the places that only see oil when running. There are also dyes that you can add to the oil and use a UV light to follow the leak back to the source.

 

[Street fighter]

We tend to focus our attention where we see the drip. You have to remember that everything gets blown to the rear and it finally drips off at the end. Oil will run along the pan rails then down the rear housing to the area around the speedo. If you say it's also wet around the speedo housing that's a good sign that it is further forward. Leaks will seldom migrate forward. I would take a good quality brake cleaner and an air hose under there and clean and dry everything. Go for a short drive and get under it right away and look for the slightest damp spot. If you don't see anything just let it sit and look under it periodically. If you see a drip start after sitting, follow it back. Things like the dipstick tube and valve body shaft seals usually only leak when the trans sits and the convertor drains down, raising the fluid level in the trans above those seals. If nothing develops sitting you now have a good idea where to look, the places that only see oil when running. There are also dyes that you can add to the oil and use a UV light to follow the leak back to the source.

I'll be cleaning it today, I'm going to put it up on ramps and give it a good cleaning. asked a trans man about the breather being the problem but he told me he did not think so because it is located behind the converter. have seen one 727 blow fluid after setting up for a long time due to breather stopped up. Will clean and see what happens.I will be running it on stands that way I can get right under it after I stop it. thanks.

 

[Street fighter]

I have seen the yoke itself leak on that year of driveshaft. Rightout the back side of the yoke. Before proceeding to far is the transmission vent functional?
There is nothing in the 727 that pumps fluid back that far. Acceleration forcing fluid past the tailshaft bearing and splash lubricates the bushing and seal.
Someone going to tell me I am full of bs i can feel it.

How can I tell if the vent is the problem? I was told that the vent was located in the front pump behind the converter. I feel that this is my problem but I have been told that it is not. the harder I drive it the worst it is,but parking it heading up a small hill will just about drain the trans of fluid if I let it sit there over night.

 

[miller]

I'm guessing your 'later' 73 727 is pretty much same as earlier units. That being said...

The tail housing bushing bore (that's a mouthful!), should have a relief slot cut in it, to halfway in the bushing bore. That slot goes towards the front of the housing, letting the fluid move back into the case. The bushing itself should have a hole, halfway through the bushing.
When the bushing is installed, into the housing bore...that hole needs to line up with the slot. If not, trans fluid has no place to go, but the easiest 'out'. Fluid there is not under pressure, but from just normal flow, but no drain, will easily flood back there.

And, of course, the seal needs to fit the shaft right. Use a light wipe of grease on the seal 'lip', before you install the yoke shaft, to help it seat.

 

[mopar 3 B]

How can I tell if the vent is the problem? I was told that the vent was located in the front pump behind the converter. I feel that this is my problem but I have been told that it is not. the harder I drive it the worst it is,but parking it heading up a small hill will just about drain the trans of fluid if I let it sit there over night.

Try parking in the other direction if possible. With the tailshaft up hill and still leaks will eliminate the yoke seal maybe?

 

[Steve Garner]

How can I tell if the vent is the problem? I was told that the vent was located in the front pump behind the converter. I feel that this is my problem but I have been told that it is not. the harder I drive it the worst it is,but parking it heading up a small hill will just about drain the trans of fluid if I let it sit there over night.

That should make it easy to spot if it's leaking that much when sitting. Also, if it leaks lots when sitting it's not case pressure from a plugged vent. In fact, a plugged vent slows the leak when sitting (air can't get in to replace the fluid). This won't be hard once you've dried it all up.

 

[Kernel Sanders]

Is it possible the leak is coming from the access cover for the tail housing snap ring release?

Also check your yoke for any ridge around where the tail seal touches.


(ref post#8) oh and I think you meant the torsion bars and torsion bar cross member, not the strut rods.

 

[zigs]

I just ran into this . I know I have a bad front seal. I'm in the process of dropping the tanny , I pull the drive line out and i'm getting fluid leaking out of the tail shaft
the hallow shaft of the drive line that goes into the tail was full of fluid. Could the leak from the front seal work its way back. Tail had not been leaking until I pulled.
this is a fairly fresh build