  Exclusive semileptonic B decays into excited charmed mesons are investigated
at order $\Lambda_{QCD}/m_Q$ in the heavy quark effective theory. Differential
decay rates for each helicity state of the four lightest excited $D$ mesons
($D_1$, $D_2^*$, $D_0^*$, and $D_1^*$) are examined. At zero recoil,
$\Lambda_{QCD}/m_Q$ corrections to the matrix elements of the weak currents can
be written in terms of the leading Isgur-Wise functions for the corresponding
transition and meson mass splittings. A model independent prediction is found
for the slope parameter of the decay rate into helicity zero $D_1$ at zero
recoil. The differential decay rates are predicted, including
$\Lambda_{QCD}/m_Q$ corrections with some model dependence away from zero
recoil and including order $\alpha_s$ corrections. Ratios of various exclusive
branching ratios are computed. Matrix elements of the weak currents between $B$
mesons and other excited charmed mesons are discussed at zero recoil to order
$\Lambda_{QCD}/m_Q$. These amplitudes vanish at leading order, and can be
written at order $\Lambda_{QCD}/m_Q$ in terms of local matrix elements.
Applications to $B$ decay sum rules and factorization are presented.
