The plunger force is transferred onto the inner modulator valve. When the sleeve wears, the converter apply pressure is reduced and TCC slippage increases.
The wear-resistant Sonnax kit prevents future wear and restores proper hydraulic clearances so fluid pressure can position the TCC modulator valve to fully apply lockup.
Common complaints with a 5R55N are high TCC slip RPM at increasing load, slip codes, and converter apply or release concerns. These complaints can be caused by wear of theTCC plunger valve and sleeve assembly due to constant oscillation by the pulse width modulated TCC solenoid.
A vacuum test fails to yield 18 in-hg or greater, or if visual wear is detected.