The 1000 series (and similar 2000 and 2400 series) is a line of automatic transmissions for on-road trucks. All are 5 or 6-speed electronically controlled units and are manufactured by Allison Transmission in Indianapolis, Indiana as well as in Baltimore, Maryland and in Erskine, Minnesota. The 1000/2000 Series is the smallest transmission that Allison manufactures. Other transmission families include the 3000, 4000, 5000, 6000, 8000, and 9000 Series, with correspondingly larger and more capable transmissions as the number increases.