The TCI Heavy-Duty Input Shaft and Drum Assembly is now available with an enhanced durability sun shell to deliver the ultimate in strength and performance. A common problem with 700R4 and 4L60E transmissions is damage to the sun shell and its inner gearing through harsh shifting or high torque conditions. Featuring a cryogenically treated input shaft, the assembly also incorporates a specially processed heavy-duty drum with a steel reinforcement ring, which is especially important for transmissions enhanced with raised line pressure to improve shift quality.