Transmission assembly for tractor

In a tractor having a front housing and a transmission casing which are arranged in series in a longitudinal direction of the tractor and are fastened together the front housing including an open rear end and a first intermediate wall, an improved transmission assembly comprising:

• an additional speed change mechanism (6) disposed within said front housing (1) and behind said first intermediate wall (1a) so as to perform a first speed-change transmission between a primary shaft (4) and a first speed change shaft (5),
• a main speed change mechanism (9) disposed within a front half of said transmission casing (2) so as to perform a second speed-change transmission between a drive shaft (7), driven by said first speed change shaft (5), and a second speed change shaft (8),
• said transmission casing (2) comprising an open front end for permitting therethrough an assembly of said main speed change mechanism (9) into said front half of said transmission casing, a second intermediate wall (2a) located behind said main speed change mechanism (9), integral boss means (2c) disposed within and around said open front end, and a bearing support frame (10) disposed within said open rear end of said front housing (1) and secured directly to said boss means;
• said primary shaft (4) and said first speed change shaft (5) being directly supported respectively by said first intermediate wall (1a) and by a front end portion of said bearing support frame (10), and said drive shaft (7) and said second speed change shaft (8) being directly supported respectively by a rear end portion of said bearing support frame (10) and by said second intermediate wall (2a);
• and
• an intermediate shaft (17) supported directly by said bearing support frame (10) for drivingly connecting said first speed change shaft (5) to said drive shaft (7).