TH400 Drain & Refill

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DoubleDingo

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Carb'ed Vortec 350; 1972 L48 350
I am about to do some drain and refills and I was wondering from those of you that done this, what was the amount of atf that came out when you dropped the pan?

I am asking so I can budget for purchasing enough atf to do 3 drain & refills and a filter change. My guess from when I did this to my 56 Sedan that had a 350/TH400 setup in it, was about 3 quarts came out when the pan was dropped. But I was 20 years younger back then and a few sleeps have happened in between now & then and a few brain cells have been sacrificed along the way too.

Thanks in advance.
 

HotRodPC

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I'd go to Walmart and get 2 gallons of the Super Tech Brand ATF. It's the cheapest you'll find, and works great. I've not have any problems with in Th350 and Th400's. It works out to be about buck cheaper per quart. You might even get 3 gallons to be sure if you're wanting to change it 3 times.
Some guys now days, just do their own flush. Drop the Pan, clean and change the filter. Buy a fitting for the radiator. Put a hose on the end of the return line and run it into a bucket to catch the old fluid, and hose in the jug to the radiator fitting to draw in new fluid, suck 3 - 3 1/2 gallons into it, and you should have recylced all the fluid with new.
 

DoubleDingo

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81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
Engine Size
Carb'ed Vortec 350; 1972 L48 350
Some guys now days, just do their own flush. Drop the Pan, clean and change the filter. Buy a fitting for the radiator. Put a hose on the end of the return line and run it into a bucket to catch the old fluid, and hose in the jug to the radiator fitting to draw in new fluid, suck 3 - 3 1/2 gallons into it, and you should have recylced all the fluid with new.

That's damn good idea!! :High 5:
 

HotRodPC

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Then if the fluid is not to horribly dirty, you can strain it, and use a pint of it, to mix with a pint of Acetone, and make your own home brew of rusty nut buster that works better than PB Blaster or WD-40. Bossman strains used trans fluid and uses it in the hydraulic system of the yard dog tow truck too. Trans fluid is some good stuff.
 

DoubleDingo

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Right where I am
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1981, 1965
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
Engine Size
Carb'ed Vortec 350; 1972 L48 350
I saw that little home brew nut buster a couple weeks ago. I need to mention it to Pop to see if he ever tried it. I have the perfect canister from my grandpa for my mix of it. It's one of those old school metal cans with the trigger and flexible metal line. He put engine oil in it lube hinges and stuff, I will putting it to used use in a different way.

The atf in the transmission now is a little on the brown-side, kinda brownish-red. Not smelly and burnt, but getting there.
 

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