The gearboxes and the rear axles

The Trakker range is equipped with ZF Ecomid 9S109 and 16S109 9 and 16 speed gearboxes in combination with the 270 and 310 Hp Cursor 8 engines; Ecosplit 16 S 151 with the Cursor 8 – 352 Hp; Ecosplit 16 S 151 OD (overdrive) with the Cursor 13 – 380 Hp; Ecosplit 16 S 181 OD with the Cursor 13 – 440 Hp; and Ecosplit 16S221 OD with the 480 Hp Cursor 13. All the 16-speed gearboxes are equipped with Servoshift assistance, with an air cylinder incorporated in the gearbox cover. The effort needed to engage the gear ratios is half what it would be with a conventional mechanical control.

Why have we chosen the Ecosplit gearboxes with overdrive on the last ratio with the Cursor 13, rather than direct drive like the road vehicles? Because the transmission elements are subject to less stress: with lower ratios, the torque multiplication and jolts due to changes in the wheel grip are less pronounced. A final drive is envisaged on the dual reduction rear axle.

The EuroTronic 2 automated gearboxes, developed by Iveco and ZF, are available on request with the 310 Hp and 352 Hp Cursor 8, in the 12AS2301 DD version, and with the Cursor 13 in the 12AS2601 OD version, both with 12 speeds. Some 4x4 and 6x6 models with right-hand drive offer the EuroTronic as standard equipment.
The EuroTronic 2 gearboxes have a totally automatic gear change logic and a semiautomatic mode, in which it is the driver who decides when to engage a gear. EuroTronic gearboxes are without synchronisers, which are replaced by gear engagement teeth. The clutch pedal has also been eliminated. To start off, the driver just selects a gear ratio and accelerates. A microchip pilots the engagement. In automatic mode, the gear change is decided by an electronic control unit that takes into account the engine speed, the available power, the resistant force of the wheels and the position of the accelerator pedal. The gear speeds are synchronised by electronic adaptation of the engine speed, which is much faster than synchronisation by friction. This solution is particularly popular in construction sites if the vehicle has to climb, because the loss of speed is minimal. On the contrary, if the driver wishes to maintain the same ratio over a difficult stretch, he can switch over to semiautomatic mode. In this case the automatic device will not perform any inadvisable actions. The EuroTronic 2 gearboxes have equipped Iveco construction site vehicles since 2001.
Double reduction rear axles: an Iveco speciality

Iveco has always specialised in double reduction rear axles, forward drive axles and gear housings, a field in which it has many years of experience. The double reduction of the rear axles comprises a pinion/bevel gear assembly, located in the central sump (ratio between 1:1.3 and 1:1.5), and epicyclic final drives located in the wheel hubs, with a constant ratio of 1:3.2. This configuration has two advantages: the small diameter of the bevel gear limits the size of the sump and increases the ground clearance. And, because rear axle demultiplication essentially takes place in the wheel hubs, the axle shafts are under less stress during the jolts of the tractive force. In this case too, sturdiness guarantees a longer life.
The 451391 rear axle, developed for 4x2 trucks, has a capacity of 13 t. The rear axles of the rear tandems mounted on the 6x4, 6x6, 8x4 and 8x8 are of two types: for “lighter” models, the 452146 and 452191 rear axles have a capacity of 10.5 t, equal to 21 t for the tandem; for the heavier models, the 453291 rear axles have a capacity of 16 t, i.e. 32 t for the tandem. All the rear axles are fitted with a differential lock; the forward axle of the tandem also has a longitudinal inter-axle differential lock.
The 5985 forward drive rear axle, for 4x4 and 6x6 models, and the special version that equips the 8x8 model, have a capacity of 9 t, they are fitted with the same hub final drives with a ratio of 1:3.2.

Simple reduction rear axles for cement mixers

The only vehicles in the Trakker range that are fitted with a simple reduction rear axle are the 6x4 and 8x4 cement mixers from the light range, which are used on roads, or on good tracks. The simple reduction rear axle keeps the kerb weight down, as do the Cursor 8 engine and the chassis with 7.7 mm rails. The MT-150 rear axles are supplied by ArvinMeritor. They have a capacity of 10.5 t, or 21 t for the tandem, and are equipped with inter-wheel and inter-axle differential locks.