Measurements of total cross sections for collision induced dissociation, proton abstraction, and charge transfer have been made for collisions of CH4+ with CD4, H-2, and Ar. The laboratory collision energies range from a few up to 400 eV, and isotopic substitutions have been made where possible to investigate any possible isotope effects, and for some reactants, to more closely identify the product ions. Cross sections for all reaction channels are observed to be small; less than or similar to 5 Angstrom(2) for the methane target, less than or similar to 0.5 Angstrom(2) for the hydrogen target, and less than or similar to 2 Angstrom(2) for the argon target. For the methane and hydrogen targets, proton abstraction is observed at low energies while charge transfer occurs for energies greater than or similar to 10 eV. The implications of internal energy present in the CH4+ projectile for the cross section measurements is discussed. In addition, decomposition of CD4H+ is addressed in terms of recent calculations related to the structure of the CH5+ ion.