727 rebuild at home

Black_Sheep said:

I made a 727 front clutch spring compressor tool from scraps I had laying around the shop. In the background is a Snap-On snap ring pliers. Expensive, but the phrase buy once, cry once definitely applies...

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That’s what I did way back when. Same pliers, probably never use them myself again.

The benefit of the aftermarket book: has tips in it to make the job easier, plus 'tricks' that have been learned over time that can add durability/performance to the trans. These are NOT in the FSM.

I

R413 said:

Air checking doesn't make them work any better. It's just a test before it's in the car.

I quit air checking after the first few.

Front clutch on 727 I just lube them well, you can move the piston side to side while a slight push down and they go in easy enough. Clamps seem like a bad idea.

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Been doing these 45 years. An old seal will push in by hand. I could count the number of new seals that pushed in on one hand. I used to freeze them with a zip tie around the seal. The clamp method works better. One turn at time on each clamp. As for air checking? It only takes one piston or sealing ring that doesnt seat right and a trans that gets put in the car to change that thinking. I mean it does take all of about 30 seconds if you have a hole in the bench before anything is reasembled in the case.
Doug

Doing an air check not only is a test of function, it also helps seat everything to aid you checking end play/ runout, whatever it's called

With the book you bought, follow it and you’ll be fine. Hole in the bench helps with assembling the rear clutch especially the piston with the inner and outer lip seals. I also stack up the front and rear drums on the pump and do an air check outside the case before install. If you run Teflon sealing rings on the reaction shaft support with a steel front drum only, they do not air check as well as stainless or iron rings at first, due to the lube in the ring lands hold the Teflon rings in place better. But once you get the rings to break free from the assembly lube, they seal really nice. I typically air check on the pump outside the case and once everything is installed in the case to ensure nothing is blocked and no lip seals or sealing rings got damaged during install. If your running aluminum front drum, you must run stainless or iron sealing rings on the reaction shaft support. Although I’m not as experienced as DVW and some others, I do build a lot of these transmissions with success in both street cars and all out drag cars.

RJ