I dont think an octalink BB will work with cranks you have if you have Truvativ BB. Truvativ has different spline configuration (12 splines vs 8 on octalink I believe). Also, you may not need a new BB. Creaking is more often an indicator that BB shell and cup threads need to be greased up. If, when you turn cranks by hand, they seem to turn smoothly, I would suggest you just grease up shell and BB cup threads (or better, use anti seize) and reinstall current BB. If problems persist, Truvativ spline BBs are pretty cheap.