ADDITIONAL CAVEATS concerning the DIRECT DRUM
One other thing to watch out for is the direct drum piston and seals.
The piston contains a small check valve (ball & seat) and every one I have seen leaks slightly. When replacing the piston seals, carefully check this valve and insure that it is, indeed, a one way valve!
You can replace the piston, or you can try reforming the seat by tapping the ball from the back side with a nail set (one with a rounded, concave tip) and hammer. A few blows will usually restore the seat to an acceptable condition. Make sure, of course, that there is no debris in the valve before doing this - or you will imbed it into the seat, ruining it forever. Don't get carried away with this, you don't want to damage the ball (it IS hard) and you certainly don't want to loosen or drive the check valve out of the piston!
Also, the holes in the direct drum should be checked for burrs, as I have seen the inner bore of the piston scratched from this. Carefully file the edges (chamfer) the holes and check the piston for damage. Deep scratches in this area will cause pressure leaks and slippage of the direct clutch.
Of course, the sealing rings install with the flair down into the drum, so that hydraulic pressure helps them seal. DO NOT attempt to re-install the piston without some kind of seal guide/protector - you WILL damage the seals.
If you can't afford one/can't find one, you may create a makeshift installation tool with some heavy 10+ mil plastic. Just wrap an appropriately sized piece around the inner and outer circumference of the drum, and install the piston carefully - making sure not to fold back the seals upon themselves. Then, before the piston bottoms, but after it has cleared the rollover from the lugs for the steels to the piston sealing surface, remove the plastic and insure none remains in the bore. Make sure you have plenty of transmission fluid coating all parts before reassembly.
After assembly of the drum and checking the clearances, it is advisable to wet-air check the drum for leaks and proper piston movement. This one is a pain, due to all the passages in the bore, but it can be done. NEVER use over 40 PSI for this.
Besides, it's neat to watch!