Information about rebuild A172/A174/TW-40E transmission
In the late nineties, four-speed gearbox A174, TW-40E, was designed on the basis of three-speed automaton А172, which was intended for the installation on mini cars. In the following, this transmission was refined several times and installed on Suzuki and Ford cars with an engine displacement of 0.7-1.3 liters. Scheduled and major repair of automatic transmissions А172, A174 and TW-40E allowed the car owners to fully restore the gearbox, ensuring its service life at 500.000 kilometers.
In 2003, the modified gearbox appeared, which received an index TW-40E. This transmission had a fully electronic control and allowed to change gears as smoothly as possible; in this, it was easy to maintain and repair.
Features of automatic transmission А172, A174, and TW-40E
The main feature of this transmission is its sparing settings, which allows postponing the deadline of the scheduled repair to 200.000 km, somewhat simplifying the car operation and reducing the car maintenance costs. The machine had a classic design with linear solenoids; it was fully controlled by automation, and the work of automatic transmission adapted to the driving style of the car owner.
A172-A174 TW-40E Scheme Diagram
When performing the oil service of this gearbox, the metal closed filter could be washed without changing it, while ensuring the required quality of oil cleaning. However, Suzuki Jimny used a standard plastic fluid filter, which was changed during every oil replacement. On older gearboxes, it was recommended to rebuild А172, A174, TW-40E with an additional main external filter, which removed all wear products from the oil, preventing critical breakdowns of the machine.
Typical problems of gearbox А172, A174, TW-40E
Today, this is a quite common gearbox for mini cars; therefore, there were no difficulties with the repair of automatic transmissions A174 and TW-40E. Most often, the car owners contacted the service in such cases: 1) when leaks appeared on the gaskets and it was necessary to restore the torque converter; 2) after solid runs, it was already necessary to restore the valve body and sort out the iron part of the box. Today, there are special repair А172, A174, TW-40E kits, which allow you to simplify the work with this transmission greatly.
Failures of oil pump А172, A174, TW-40E
Traditionally, one of the most loaded elements of all machines is an oil pump, which provides an increased pressure in the system, ensuring proper lubrication and valve body operation. If there are problems with oil seals and sleeves, the pump no longer provides the necessary pressure; it leads to premature wear, and soon such a machine requires a full restoration. As the prevention of such failures, it is recommended to change oil seals and sleeves as a kit during each opening of the machine.
The pump valve wears out on the gearboxes with a solid mileage; such repair of automatic transmissions А172, A174, and TW-40E implies the use of appropriate repair parts or complete replacement of the oil pump.
How to extend the service life of automatic transmission А172, A174, TW-40E
To extend the service life of this machine, it was necessary to exclude an increased load on this transmission, as this gearbox poorly tolerated overheating and long operation at high speeds. After the long parking in winter, it was necessary to warm oil in the gearbox, as thick cold oil poorly lubricated the transmission, leading it to the premature wear and tear. Scheduled major repair of automatic transmission А172, A174, TW-40E was carried out on the relevant runs, indicated by the car manufacturer; during such work, it was necessary to use only original spare parts.
Valve body scheme
Solenoid diagnostic TW-40E/A172/A174