Torque Converter Slip Calculator

Inputs

Measured engine speed (n_e)

Actual logged or observed engine RPM.

rpm

Road speed (v)

Vehicle speed at the measured RPM.

km/h

Tire diameter (D)

Rolling tire diameter.

Transmission ratio (G)

Selected gear ratio.

Final drive ratio (F)

Axle or differential ratio.

Transfer ratio (T)

Use 1.0 if there is no transfer case or auxiliary ratio.

Default result

Slip

36.7%

Out of tol.

Also computed

Slip RPM806rpm

Locked RPM2,194rpm

Wheel speed840.3rpm

Overall ratio2.611

Method notes 2 notes

Positive slip means measured RPM is higher than locked mechanical RPM. Negative slip usually means tire diameter, speed or ratio data is off.
Automatic transmissions can show different slip under load, coast, lockup and transient shift conditions.