PPE Diesel 128060000 Heavy Duty PTO Side Covers GM Allison 1000 2000 Series RawDescription PPE Diesel 128060000 Heavy Duty PTO Side Covers GM Allison 1000 And 2000 Series Raw Made from cast aluminum, these covers add strength to center of the transmission case eliminating trans oil seepage at the mating surface. Cooling fins double the surface area (60. 74 sq. in.) when compared to stock (30. 62 sq. in.), which increases heat dissipation from the transmission oil. Kit comes with the covers, mounting hardware and gaskets.