Hey Guys! My posi-trac system makes a clicking noise in the rain and I am simply looking to upgrade my rear axle. I want the Ford Nine inch but I am not sure what the best gear ratio would be for my car. I drive a 99 Sn95 Base model with some minor engine upgrades CAI, BBK throttle body, and a Bama Tune. As far as other modifications I have SR Performance sway bars and Coilovers. My driving style is spirited on the back roads! What would be the best rear gear ratios for my car! Thanks for the help.
You aren't making anywhere near four digit horsepower so you don't need a 9 inch. It sounds like you need to diagnose your root issue. A clutch pack rebuild for your current axle is easy and a couple hundred bucks.
What motor/trans are you running? That'll make a huge difference. I've had 2.73, 3.27, 3.73, 4.10.... my current car is still rocking the 2.73 and will be getting upgraded to 3.27 or 3.55 when it comes time as this car is 99.4% daily beater. 9" is way overkill and you'll be just fine rebuilding the factory LSD and putting gears in it.
The 8.8 can handle loads of power. It would be much cheaper to just upgrade to a 31 spline diff and axles.