Transmission general data

The Allison 2000 series includes modifications 2100, 2200 and 2300. This type of transmission was designed for light commercial vehicles operating in sectors of transportation and public transport. These transmissions are equipped with a turbine-driven power take-off mechanism with the N-locking option, and with a parking brake. Transmissions of 2000 series may have up to 6 gears, including overdrive, and be equipped with an advanced electronic control system of the 5-th generation, which provides more efficient operation and more diagnostic capabilities. These transmissions are reliable and highly efficient and can transmit power equal up to 224 kW ( 300 HP) in modifications with narrow or wide ratio coverage. As a rule these transmissions are used for commercial vans, drop-side trucks with a manipulator and all kinds of special equipment with a load capacity up to 13.6 tons ( 3000 lb). These transmissions are installed on almost all brands of trucks, buses produced in Europe (except MAN), Korea, and China. The instantaneous connection between the engine and the gearbox ensure precise modes of operation regardless of the cargo condition and the road quality.

Accurate gear shifting without interruptions of power ensures the best speed characteristics and fuel economy. Fully automatic transmission allows the driver to pay more attention the driving process that is more important in difficult and tedious road conditions. The transmission electronics can be programmed to prohibit the vehicle movement when the auxiliary equipment is used. Consequently, the auxiliary equipment will be inaccessible when the vehicle moves. This feature provides additional security in operation.

Technical issues and repair guidelines

The main repair problems are related to the auxiliary power take-off equipment, torque dividers, and the main one – the cooling process or heat exchanger. Designers of these transmissions quite consciously reduced the transmission resource by means of cooling.

There are 3 main problems related to valve bodies of Allison 1000/2000/2400:

1.Sticking E-shift. When the valve sticks TCM detects that the pressure sensor doesn’t change the status and sets the trouble code P0872- after that the gearbox switches to the failsafe mode.

2.F-trim valve sleeve. The inside diameter of the sleeve wears out, leading to the torque converter clutch surge and trouble code P0741 – indicating the torque converter clutch slipping. . When lock-up stops operating and the P0741 code sets, the torque converter can overheat the ATF, causing damage to the torque converter and rapid deterioration of the ATF.

3. Warped castings. Valve bodies for these transmissions do not have separator plate gaskets, therefore it is required that two halves of the valve body should be flat sanded for protection from cross leakages. In this case locating pins should be removed to flat sand the valve body.