Push button 727 leak

[wagonman]

About a year or so ago I posted about a leak coming from the park cable housing. This was when I was helping a buddy out of state. Fast foward to today. The car is at my shop and I can play with this leak. In that year I did my research and found Sonnax has a Pressure control valve that helps with convertor drain back. When I pulled the pan today it dam near filled a 7qt pan. That was after leaking on the floor for a few weeks. Convertor drain back Yep. The new valve has a one way check valve for this and other issues. I will pull the park lock housing again as I have another one to compare and measure. Hope this keeps the pan level in spec, we shall see.

also shout out to 493 Mike for sending me parts for free. Also TransGo has a new manual valve in their TF2 shift kits for this.

 

[dvw]

Seldom are the tail shaft housing or the park housing assembly flat. I disassemble the pawl parts from the housing. Then stone them both flat. It takes a little bit of work. Seal the crimp on the cable with heat shrink. Use the type with the glue in it. New O rings at the cable and the rear band anchor pivot pin. Fill the rear band pivot pin bore recess with RTV after installing the pin. Use a little RTV under the head of the long tail shaft parking pawl pivot bolt as well. Never used an anti drain back repair. But if everything is sealed up it doesn't matter what the fluid height is. Just did a 64 trans for a member here using these suggestions. He reports back no leaks.
Doug

 

[Dave6T4]

I use a deep pan with filter extension and just fill with factory recommended quantity. I remark ADD and FULL marks on dipstick with small drill hole.

 

[VANDAN]

I use a deep pan with filter extension and just fill with factory recommended quantity. I remark ADD and FULL marks on dipstick with small drill hole.

Dave, I have to ask, would the Add &Full marks change, as the deep pan just adds extra fluid to the quantity ? I'm going this route with my '63, and I haven't changed the dipstick to a longer one...

 

[wagonman]

Seldom are the tail shaft housing or the park housing assembly flat. I disassemble the pawl parts from the housing. Then stone them both flat. It takes a little bit of work. Seal the crimp on the cable with heat shrink. Use the type with the glue in it. New O rings at the cable and the rear band anchor pivot pin. Fill the rear band pivot pin bore recess with RTV after installing the pin. Use a little RTV under the head of the long tail shaft parking pawl pivot bolt as well. Never used an anti drain back repair. But if everything is sealed up it doesn't matter what the fluid height is. Just did a 64 trans for a member here using these suggestions. He reports back no leaks.
Doug

All good ideas especially the heat shrink. With the VB out and everything drained I pulled the park lock housing access plug and more fluid poured out. The leak is were the cable and O ring go in, constant drip. I have a spare cable to bench test for leaks. Cleaned it all up and tilted it in a vice poured some gas in it and still seeped a bit. Got a green coated O ring from my stash, think R134a style and no more seep. On the right path.

 

[dadsbee]

As DVW pointed out, make sure that leak isn't working it's way around from the rear pivot pin. I did every seal on my SBird, and the pan, only to find the real culprit was the pivot pin O rings. Cleaned the area spotless and coated with PRC (Aircraft fuel tank sealer) and she's leak free for the first time in 30 years!

 

[Dave6T4]

Dave, I have to ask, would the Add &Full marks change, as the deep pan just adds extra fluid to the quantity ? I'm going this route with my '63, and I haven't changed the dipstick to a longer one...

I am not putting the deep pan on to add extra fluid capacity as many would. I put it on to provide extra space for the torque converter fluid to drain back to, with factory (8 quart) fill quantity. With an empty converter, I add 8 quarts to the pan, and fire the engine up in neutral to let the converter fill with fluid. After warm up, I check the new FULL level on the dipstick and mark it with a small drill hole. Then I measure the distance between the factory FULL and ADD marks, and drill a new ADD mark hole that distance below the new FULL mark. The original dipstick will accommodate these new marks, so a longer stick is not needed. This allows more room to contain converter drain back, putting less stress on pan gasket and dipstick tube o-ring.