The Iveco EuroTronic gearbox 12 AS 2301 D.D./O.D. is mechanical with electro-pneumatic control. The driver can choose whether to program gear selection/engagement manually or automatically. The shafts and gears have helical toothing that reduces operating noise. The main shaft gear coupling is obtained with sleeves with front toothing. The splitter and epicyclic reduction gear unit engagement is synchronized. The speeds are selected with finely staggered ratios and can be engaged in succession with the coupling of the epicyclic reduction gear unit ”ERG” and the ”Splitter” slow or fast speed unit. On engaging the ”ERG”, the speeds of the main shaft are doubled. The ratios obtained in this way are further doubled with the engagement of the ”Splitter”. Each single ratio is thus divided into a fast or slow ratio.
OVERHAULING THE GEARBOX
The gears, synchronizer rings, coupling bodies and sliding couplings must show no sign of failure or excessive toothing wear. The main shaft must have no indentation, especially on the sliding surfaces of the gear rotation and coupling sleeves. The reverse idle gear shafts must have a polished surface free from scoring.
The gearboxes must show no sign of cracking and the bearing seats must be neither damaged nor worn, so as to prevent the outer rings of the bearings from turning in their seats. Check the shoulder spacers are neither worn nor damaged. The gear coupling forks must show no sign of cracking and the relevant control rods must slide freely, but without any appreciable play, in their guide seats. Check that the shoes of the drive forks are fully efficient. Check that the holes, grooves and lubrication pipes are not obstructed by grease or foreign bodies.
Removing the splitter synchronizing device
Put the synchronizing device assembly (1) on the workbench, cover it with a cloth to prevent the pins (8) and springs (7) getting lost during subsequent dismantling. Holding back the synchronizing device ring (6), lift the synchronizing device ring (2); these will get freed: toothed ring (5), three clips (7) and three pins (8). Remove the key (4) and extract the toothed sleeve (3) from the toothed ring (5).
Fitting the splitter synchronizing device Figure 77
Insert the three springs (7) and three pins (8) in the synchronizing device ring (1) and keep them in their seat with the centring pins 99370499 (2). Position the toothed ring (4) on the synchronizing device ring (6). Fit the synchronizing device ring (1) in the toothed ring (4) and on the synchronizing device ring (6) so that the centring pins 99370499 (2) drive onto the pins (5) of the synchronizing device ring (6). Press on the synchronizing device ring (1) uniformly so that the components of the assembly fit together correctly. Take out the centring pins (2).
Spread IVECO sealant 1905685 onto the mating surface of the middle box (5). Fit the eyebolt 99368811 (1) onto the front box (2). Using ropes and a hoist, lift the box (2) and position it coaxially to the middle box (5). Insert the rods (6), of suitable diameter, into the seats in the front box (2) of the oil pipes (7 and 8) and into these too. Lower the box (2) checking that the rods (3 and 4) and the oil pipes (7 and 8) are correctly inserted in their seat. Remove the eyebolt (1) and the guide rods (6).