We analyze the 3D kinematics of a sample of \sim 4400 red clump stars ranging between 5 and 10 kpc from the Galactic center and up to 3 kpc from the Galactic plane .
This sample is representative for the metal-rich ( [ Fe/H ] = -0.6 to 0.5 ) thick disk .
Absolute proper motions are from the fourth release of the Southern Proper Motion Program , and radial velocities from the second release of the Radial Velocity Experiment .
The derived kinematical properties of the thick disk include : the rotational velocity gradient \partial V _ { \theta } / \partial z = -25.2 \pm 2.1 km s ^ { -1 } kpc ^ { -1 } , velocity dispersions ( \sigma _ { V _ { R } } , \sigma _ { V _ { \theta } } , \sigma _ { V _ { z } } ) | _ { z = 1 } = ( 70.4 , 48.0 , 36.2 ) \pm% ( 4.1 , 8.3 , 4.0 ) km s ^ { -1 } , and velocity-ellipsoid tilt angle \alpha _ { Rz } = 8.6 \arcdeg \pm 1.8 \arcdeg .
Our dynamical estimate of the thin-disk scale length is R _ { thin } = 2.0 \pm 0.4 kpc and the thick-disk scale height is z _ { thick } = 0.7 \pm 0.1 kpc .

The observed orbital eccentricity distribution compared with those from four different models of the formation of the thick disk from Sales et al .
favor the gas-rich merger model and the minor merger heating model .

Interestingly , when referred to the currently accepted value of the LSR , stars more distant than 0.7 kpc from the Sun show a net average radial velocity of 13 \pm 3 km s ^ { -1 } .
This result is seen in previous kinematical studies using other tracers at distances larger than \sim 1 kpc .
We suggest this motion reflects an inward perturbation of the locally-defined LSR induced by the spiral density wave .