Guided ion beam techniques are used to measure cross sections as a function of kinetic energy for the reactions of M(+) = Ti+, V+, and Cr+ with SiH4. The major low-energy process in all three systems is formation of MSiH(2)(+) + H-2. At higher energies, the formation of MH(+) + SiH3 dominates the reactivity. Minor ionic products include MSiH,+ (x = 0, 1, 3), as well as SiH3+ in the V+ and Cr+ systems. Variation of source conditions allows the effect of electronic excitation on the reactivity of these systems to be studied. The results indicate that the reactions are more efficient for the low-spin doubler (Ti+), triplet (V+), and quarter (Cr+) excited states. The reactivities of these systems may be understood in terms of simple molecular orbital concepts and spin conservation. The thresholds for the various reactions are evaluated to yield 0 K bond dissociation energies for M(+)-Si, M(+)-SiH, M(+)-SiH2, and M(+)-SiH3 of 2.54 +/- 0.17, 2.30 +/- 0.11, 2.17 +/- 0.07, and 1.69 +/- 0.18 eV, respectively, for M = Ti, of 2.37 +/- 0.15, 2.09 +/- 0.12, 2.02 +/- 0.09, and 1.54 +/- 0.16 eV, respectively, for M = V, and of 2.10 +/- 0.16, 1.02 +/- 0.29, 0.99 +/- 0.14, and 0.78 +/- 0.18 eV, respectively, for M = Cr. The present results are compared to those previously reported for the reactions of Ti+, V+, and Cr+ with methane.