Lube Gard will only help aggresive clutches. There are other reasons why the Allisons will downshift hard. Rear wheel sensors, driveshaft yoke, or weak grounds in the electrical system to name a few.
Build the trans and use my Ratio-tek pump and valve body kit. Make sure there is no trans tune or TCM fooler installed or you will break the trans in half. TCM must be stock.
You will hardly ever see clutch material in the pan on a Allison. They will heat check the steels badly and glaze the frictions, but they will not shed material till they get destroyed. Now the converter clutch will shed and plug the heat exchanger.