The Lie group Sol(p, q) is the semidirect product induced by the action of R on R which is given by (x, y) 7→ (ex, e−qzy), z ∈ R. Viewing Sol(p, q) as a 3-dimensional manifold, it carries a natural Riemannian metric and Laplace-Beltrami operator. We add a linear drift term in the z-variable to the latter, and study the associated Brownian motion with drift. We derive a central limit theorem and...