727 trans leak

[dan juhasz]

I have a leak in the rear of the trans. Thought it was the pan gasket but not so. There is what appears to be a button pressed into the main body of the trans, the tailshaft has an ear that partially goes over this button to keep it in place. Doesn't look threaded, no bolt head, not sure what I need to fix or what the piece is called. Help!
Dan

 

[miller]

The 'button' your asking about, is the end of a straight shaft. Can't remember what it's called. But, point is, pretty sure that shaft takes an o-ring, that seals it off. The tab simply helps to keep the shaft from backing out. Sounds like the o-ring is dead.
Find a parts break-down diagram, and you'll be able to pick out the shaft, and it's o-ring.

 

[furyus]

Its the pivot shaft for the low reverse band. Yes there's an O ring on it. You have to drop the pan,loosen the band adjuster, remove tail shaft housing , push out the pivot pin, and put on a new O ring. A factory service manual would be a big help.i did it with the trans still installed.

 

[MT_Mopar]

The first part of this video shows the shaft with O ring install.

 

[dvw]

Not necessary to take it apart. I have fixed more than a few. Tap the pivot pin in and make sure it is bottomed. Clean with brakleen and blow dry. Apply grey RTV in the depressed area. Smooth with a thin putty knife (works well of the knife is wet).
Doug

 

[furyus]

Not necessary to take it apart. I have fixed more than a few. Tap the pivot pin in and make sure it is bottomed. Clean with brakleen and blow dry. Apply grey RTV in the depressed area. Smooth with a thin putty knife (works well of the knife is wet).
Doug

That's what those lazy bastards at ATI did to my transmission. Needless to say, it started leaking after warranty.

 

[dan juhasz]

Thanks for the excellent info. I'm starting to wonder if indeed this shaft gas just backed out. The video shows the shaft not having a head and the installer says it ends up being flush. Mine is sticking out of the case quarter to half inch, only thing stopping it coming out further is the ear on the tailshaft.

 

[miller]

Mine is sticking out of the case quarter to half inch, only thing stopping it coming out further is the ear on the tailshaft.

That's why that ear is there. Shaft is simply a floating pivot, sealed via the o-ring. Sounds like the trans has some time on it. Suggest not only replacing the o-ring, but pulling the shaft, and polish it. Probably has some build-up on it...why it's moving around.