Hey Guys, This one is a little puzzling..... I own a 2006 Crown Victoria LX My mechanic neighbor replaced my rear axle with a police axle (had no choice, a new one would have been a ton of money in California) and it threw the speedo way off because of the change in ratios. I'm now a little...

I have a 96 grand marquis ls with the digital dash and I would like to swap out the 2.73s for 3.55s how do I reprogram the speedometer?

So i own a 2009 Mercury Grand Marquis limited edition, im planning on swapping out the rear axle (2.73) for a posi lock (3.73?) Can i just remove my axle and swap in a new one or are there other things i need to add or remove...