Flushing an A-727-B transmission

What is the best fluid for flushing a 727 tranny?

I'm looking to flush a transmission that has been setting for a bit and is currently not running in forward - although it was running fine for some time. Came home one evening after commuting to work, parked it, opened my gate, hopped in and put it in drive and CLANG! I warn't not goin' forerd no more. Had to do a reverse donut in my neighbor's back yard to retreat into my yard with m'tail betwixt (betwixt?) my legs.

I've replaced the valve pack and air tested the clutches to no avail. Being a stubborn curmudgeon, I just need something to convince me I'm not jumping the gun dropping the tranny and replacing it (the PK number suggests the tranny is not original). <img src="http://forums.aaca.org/images/graemlins/smirk.gif" alt="" />

Chris in NC

drop the pan, change the filter, refill with dextron fuild

Sounds like you broke the low band it won't move with out it.

Hey Rick:

Low band, huh? I wonder if breaking that was the "clang" I heard when I placed it in park to get out and open my gate. I bought an A-727-B rebuild manual. Whaddaya think of just replacing the band for first try? When I was underneath the thing - more than once - it's relaxing - I didn't really see any traumatic damage, but not being an auto tranny guru, that's not surprising.

Chris in NC

Not the low band or reverse would not work.

First gear in D or 2 position does not use the band.

You could have fried forward clutches or stripped splines in a planetary or annulus gear.

But to replace the rear band the entire transmission must be taken apart.

Last out, first in.