TH400 Billet Steel Forward Drum and Billet Input Shaft with Modified Lube Circuit. TCS has introduced a NEW INPUT SHAFT for the Turbo 400 that has the torque converter lube holes removed from the shaft to deliver superior strength. Drum is machined from 4140 HTSR billet steel. Input shaft is made from 300 Maraging steel. Shaft to drum spline count has been increased from 30 to 35 splines for extra contact and strength. Overall drum and input shaft weight is 2.50 lbs lighter than the OEM drum and shaft with major weight reduction on the O.D. The input shaft is permanently located in the drum by a shoulder stop and snap ring.