of the two ratio stages k 1 k 2 the front mounted group gv is designed as a splitter group the idler gear of the first ratio stage k 1 is rotatably supported on the input shaft w ge which is in driving connection via a separating clutch k with a prime mover not shown constructed as an internal combustion engine the idler gear of the second ratio stage k 2 is rotatably supported on the main shaft w h the fixed gears of both ratio stages k 1 k 2 are visibly situated non rotatably on the input side extent of countershafts w vg1 w vg2 of the main transmission hg the synchronized constructed shift clutches of the front mounted group gv are combined in a common shift set sv the range change group gp rear mounted by drive technology is likewise built of two speeds but in planetary design and with a simple planetary gearset the sun gear ps is non rotatably connected with the output side extent of main shaft w h of the main transmission hg the planet carrier pt is non rotatably coupled with the output shaft w ga of the group transmission the ring gear ph of the planetary gearset is connected with a shift set sp having two shift clutches whereby the range change group gp is alternatively shiftable by the connection of the ring gear ph with a fixed housing part to form a slow drive speed l and by the connection of the ring gear ph with the main shaft w h or the sun gear ps to form a fast speed.