Hub repair FORWARD CLUTCH K114 / TOYOTA CVT

During vehicle operation, a natural and inevitable process of wear and tear of automatic transmission components occurs.
An automatic transmission is a technically complex unit, the stable operation of which depends on the correct operation of all its components.
As a rule, when damaged or fails one component it “pulls along with itself” and gradually destroys those closest to it. This can be clearly seen in the example of internal hubs.
A problem that often occurs is when, when troubleshooting transmission components, a technician discovers notches on the hub left by the steel teeth of the friction discs that engage with the teeth of the hub.

Reasons for the appearance of notches on the hub:

1.Use of different types of metal in transmission components.

Many automakers, in order to reduce the weight of components, use soft aluminum as a hub material, while the base of the friction disc remains steel.
In this case, the steel disc will inevitably form notches over time, the depth of which will depend only on the driving style and operating conditions of the car.

2. Vehicle operating mode.

Sudden accelerations are detrimental to automatic transmission components.
With kick down, there is a sharp increase in engine speed and power, which is accompanied by a sharp shift into gear. The friction discs hit the surface of the hub.
In this case, even the use of the same types of metal on mating components does not significantly guarantee the absence of damage. Even steel hubs develop significant nicks.

Why are notches on transmission hubs and drums so scary?

A hub is a kind of drive or driven gear driven by a clutch pack, which consists of steel and friction discs.
As you know, oil pressure acts on the piston, compresses and decompresses the discs among themselves, and this is how the clutch is engaged/disengaged.
This process is accompanied by free movement of the disks relative to the hub, the disks are in close contact with each other, and the clutch works correctly.
The notches on the hub prevent the free movement of the disks relative to the hub, the teeth of the disk get into the notch, the disk gets stuck, the disks do not form a rigid adhesion to each other, the disks slip,
which is characterized by a loss of dynamic characteristics of the car in a certain gear. Slipping of the discs is accompanied by an increase in the temperature of the clutch pack, as a result of which the discs overheat and burn out.
In some cases, the clutch pack discs are “tightly” welded together, and the clutch remains forever in the closed state. Which entails more serious damage.

The MAKTRANS company technical base using laser welding equipment allows us to restore damaged hubs, which is much cheaper than buying a new part.
 

A pre-disassembled part is installed in a laser welding machine.

Metal fusing is carried out over the damaged parts.

We receive the part ready for installation on the transmission.