I had to replace my rear end a while ago, I shattered the pinion and didn't have enough money so I just used one from my non running 86 Cherokee with the 2.8 turd and ax5 to get me by for a while ....problem is I have a 4 speed and on the highway its turning around 3000 rpm at 55, I finally have enough cash, so my question is what gear ratio would be best to replace it with ... I am looking mostly for fuel economy ... any advice helps...thanks-chris