The Michel parameters and the average τ-neutrino helicity are measured using correlations between the decays of the τ+ and τ- produced on the Z resonance and observed in the ALEPH detector at LEP. The Michel parameters, ρl, ηl, ξl, (δξ)l, are determined from τ -> lνlντ with l = (e, μ), and the average τ neutrino helicity, <h(ντ)>, from τ -> hν with h = (π, ρ, a1). The results obtained with e-μ universality are: ρl = 0.751 +/- 0.039 +/- 0.022, ηl = -0.04 +/- 0.15 +/- 0.11, ξl = 1.18 +/- 0.15 +/- 0.06, (δξ)l = 0.88 +/- 0.11 +/- 0.07, and the average τ neutrino helicity <h(ντ)> = -1.006 +/- 0.032 +/- 0.019. No significant deviation from the Standard Model V-A prediction is observed.
