Types of repairs

• Valve body housing repairе
  • Pressure modulator valve channel and torque converter lock-up channel
  • Clutch valve channel K1, K2 and K3
  • Hydraulic accumulator channels

  TF-81SC automatic transmission valve body housing repair

The automatic transmission TF-81SC was developed by Aisin Warner in 2003, as a modification of the TF-80SC for engines with a volume from 2 to 4 liters, and a torque of up to 450 Nm. Depending on the automaker, the box may have the designation AF21 - Ford, AW6A-EL - Mazda.

To control the operation of the gearbox, an electromechanical unit is used. The control unit consists of a body and solenoids, Automatic transmission mechanical part oil is used as the hydraulic oil . The solenoids perform the basic function of setting the operating modes of the automatic transmission - gear shifting, torque converter locking, Park / Reverse / Drive switching.

The reason for diagnosing the operation of a valve body is usually such types of malfunctions as thumps during shifting, floating rpm when driving at a constant speed, unclear gearshifting and slips . After reading the error codes, the valve body is dismantled for a more detailed inspection and verification of the operability of individual sections.

In addition to solenoids, inspection and diagnostics are also subject to the valve body housing. The housing consists of several parts (plates) forming channels for transmission fluid. The pressure in the channels is formed by electromechanical valves (solenoids) and then transmitted to the  mechanical part, due to which the control of the AT operation is carried out.

In the new valve body, the clearance between the solenoid plunger and the valve channel wall corresponds to the technological dimensions and provides the working pressure of the oil. With the time of operation, the oil is contaminated by mechanical chips of rubbing parts of automatic transmission (friction, drive mechanisms). When getting into the valve body channels , such oil causes abrasion of the walls of the valve body channels in the places of contact with the solenoid plunger, as a result of which the nominal pressure is violated and, consequently, symptoms of malfunctions appear.

To determine the problem areas, the specialists of Maktrans company  use diagnostic equipment, which makes it possible to determine the integrity of the valve body channels. In the diagnosed channel , when a plunger is installed, a reduced pressure is created, if the pressure is maintained, then the channel is operational, if pressure is released, then the wearout of valve body channel is present.

Examples of damaged valve body channels. Damage in the form of scratches and clear spots of contact of the plunger and the walls of the channel.

For the repair of damaged areas specialists Maktrans company  use the method of channel restoration through the installation of reinforcing bushings. The damaged channel is reamed, after which a bushing is installed, the internal diameter of which completely corresponds to the technological dimensions and provides the working pressure of the oil in the valve body.

Manufacture of bushings is carried out on CNC machines  from a material similar to the material of the valve body (aluminum alloy), which allows you to accurately repeat the mechanical properties and restore the channel to the original state of the new valve body.

Depending on the detected defect, any part of the valve body can be repaired.
For floating rpm and thumps when shifting gears - the installation of the bushing in the channel of the pressure modulator valve and the lock-up channel of the torque converter.

In case of indistinct gearshifting or slipping when changing gears - repair of the clutch valve channel K1, K2 and K3 is inevitable.

Low pressure in the valve body means you have to repair the channels of the valve body accumulator.

After repair, a re-inspection and assembly of the valve body is carried out. The next step is to check the valve body in the automatic transmission of the working car. Each reconstructed valve body undergoes an obligatory test drive with verification of all operating modes of the automatic transmission. The applied repair technology is recommended as an affordable and high-quality alternative to buying a new hvalve body. For all performed repairs , a 1-year warranty is provided with no mileage restriction.

-TCC lock-up control valve replacement

-Accumulator bushing replacement

Symptoms:

- Delayed engagement and thump when shifting to Drive

- Tough Neutral

- Floating rpm on the 4 th, 5 th and 6 th gears

- TCC codes

If the valve body fails, an error Opel P0869 is detected- high pressure of transmission fluid 

 Citroen C4, C5, C6, C8,  DS4,
 Peugeot 307, 308, 3008, 407, 408, 607, 807, 508, 5008, RCZ,
 Volvo S70, XC70, C30, C70, S60, V60, S80, V70, XC60, XC90
 Mazda CX9, CX7
 Opel Insignia, Zafira
 Alfa Romeo Brera, Guilia
 Ford Fusion, Galaxy, Mondeo, S-Max
 Hyundai Veracruz
 Land Rover Freelander
 Renault Espice, Vel Satis
 Saab 93, 95