  Nonlinear spin precession has been observed in 3He-B in large counterflow of
the normal and superfluid fractions. The new precessing state is stabilized at
high rf excitation level and displays frequency-locked precession over a large
range of frequency shifts, with the magnetization at its equilibrium value.
Comparison to analytical and numerical calculation indicates that in this state
the orbital angular momentum L of the Cooper pairs is oriented transverse to
the external magnetic field in a ``non-Leggett'' configuration with broken
spin-orbit coupling. The resonance shift depends on the tipping angle theta of
the magnetization as omega - omega_L = (Omega_B^2 / 2 omega_L)(cos(theta) -
1/5). The phase diagram of the precessing modes with arbitrary orientation of L
is constructed.
