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727 trans leak

Rooster27

Well-Known Member
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Hey guys hope all is well! I have a leak coming from rear of trans right above the trans pan. I have no idea what this part is called but its circled in red. I'm guessing there is an o-ring in there that has worn out. Any advice on how to fix is greatly appreciated!

IMG_20200625_203733.jpg
 
I had the exact same issue. It is the end of some internal shaft that is sealed with an o ring. A local transmission guy told me that i could just goop some silicon over it or pay him $130.00 to drop the pan, remove the valve body, and fix it correctly. I paid him the money.
 
I had the exact same issue. It is the end of some internal shaft that is sealed with an o ring. A local transmission guy told me that i could just goop some silicon over it or pay him $130.00 to drop the pan, remove the valve body, and fix it correctly. I paid him the money.
Thank you!
 
It's not a difficult repair, but could be a messy one without a lift or a drain plug installed in your trans pan. If you attempt the repair yourself, take care to keep the valve body clean and free from debris.
 
There is an O ring on the shaft. By pulling the pan, tailshaft, and low/reverse band linkage it can be done in the car. But it's not really necessary. When I do a trans I always fill this cavity with RTV. Tap the shaft all the forward. Brake clean and blow dry 2-3 times. Squeeze in RTV and smooth with a putty knife. It's pretty easy.
Doug
 
There is an O ring on the shaft. By pulling the pan, tailshaft, and low/reverse band linkage it can be done in the car. But it's not really necessary. When I do a trans I always fill this cavity with RTV. Tap the shaft all the forward. Brake clean and blow dry 2-3 times. Squeeze in RTV and smooth with a putty knife. It's pretty easy.
Doug

It is the low/reverse band lever pivot shaft, has 1 or 2 "O" rings (depends on year) on it to seal it.
Simple fix above with RTV should work.
I would use the Mopar ATF RTV, it seems to seal really good. Your trans builder won't like it because it's a lot to cleanup off the case when doing a rebuild.
 
It's not a difficult repair, but could be a messy one without a lift or a drain plug installed in your trans pan. If you attempt the repair yourself, take care to keep the valve body clean and free from debris.
Yeah, I just replaced the pan gasket on there because that was a whole mess and leaking and yeah it gets messy, I guess it wasn't too bad I suppose.
 
There is an O ring on the shaft. By pulling the pan, tailshaft, and low/reverse band linkage it can be done in the car. But it's not really necessary. When I do a trans I always fill this cavity with RTV. Tap the shaft all the forward. Brake clean and blow dry 2-3 times. Squeeze in RTV and smooth with a putty knife. It's pretty easy.
Doug
So i can tap that shaft all the way forward without dropping pan and linkages, brake clean and then blow dry for a few min and squeeze the rtv in there?
 
No. You can tap it forward until it bottoms. This will give a larger cavity for the RTV. The shaft removes from the back. Hence the tab covering it on the tail shaft. The only thing holding the shaft in place is the O ring and the side load of the band linkage.
Doug
 
No. You can tap it forward until it bottoms. This will give a larger cavity for the RTV. The shaft removes from the back. Hence the tab covering it on the tail shaft. The only thing holding the shaft in place is the O ring and the side load of the band linkage.
Doug

Ok so I need to drop pan and disconnect linkages? Having trouble following.
 
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A local transmission guy told me if a 727 isn't leaking fluid, it's out.

Don't scold me for posting this, it's supposed to be funny.
 
Ok so I need to drop pan and disconnect linkages? Having trouble following.
Only if you want to change out the O ring. You can apply the RTV without removing anything. To apply RTV follow the instructions in post #6
 
Only if you want to change out the O ring. You can apply the RTV without removing anything. To apply RTV follow the instructions in post #6
Excellent! Thank you!
 
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