#25S – 389701D. 5R110 (Late 99 Tooth) Billet Intermediate Shaft. TCS has addressed the weakest part of the 5R110 transmission with our 5R110 billet intermediate shaft, also called the center shaft. Made from 300M billet steel and heat treated for added strength and durability. This is an excellent upgrade for diesel, off-road and drag racing applications. Radius increased in critical load areas to withstand the increased power output of today’s vehicles.