Find manual and automatic transmissions from Eaton/Fuller, Allison, Spicer, Mack, Rockwell, ZF, Meritor, and Detroit for Class 5-8 commercial trucks, as well as transmissions for construction equipment, agriculture equipment, and other heavy machinery. Listings include 5-speed through 18-speed manuals, automated manual transmissions like the Eaton UltraShift and Detroit DT12, and Allison automatics from the 1000 series through the 4000 series. Filter by brand, speed count, condition, and price to find the right replacement transmission.