Well, after recalibrating my speedo a long time ago, I later noticed that it's 4mph off. So now, I'm wanting to recalabrate it better. I'd rather have it read slow then fast. So as I ask my friend who's a Service Manager at a Dealership in Socal, if he can get me a 37T gear. Well turns out there is no 37T. It jumps from 36T to 39T. Well taking into account of the actual tire size it could be a bit slower or faster. And there is no 38T either. What a PITA. So I jsut ended up asking him to get me a 36T and a 39T.
I have a suspecision that my Jeep runs better when the speedometer is a bit slow then fast.