Yes, my FX4 had an open differential. It came from the factory with open 3.55s. The open diff on an off road package sounded absolutely ludacris to me too. I have the original window sticker too with the FX4 package (with included rancho shocks, skid plates, 17s and "all terrain" tires)

Apparently GM did the same thing in the early 2000s.. standard open diff on Z71 equipped trucks.

But I have since upgraded to a TrueTrac.

 

Your in luck than! I would go aussie or spartan locker. As for the mustang/explorer as long as its 31spline and not the 28 it will work. You will most likely need to rebuild the ls unit too.

 

Any options for the front?I would like a 4x4 not a 4x2 or 4x3.I don't want to break the bank though.

 

There's a reason the front doesn't come locked. (parts breakage) a independent front end doesn't like to be locked. Too hard on parts

 

I beg to differ. I'm currently running a detriot truetrac in the front and rear and have had 0 parts breakage due to the locked front diff.

 

But how hard do you wheel it? I've seen lots of off road mags try to make an Ifs system work with a locker and it was always breaking cv shafts. They even put a 1 ton Ifs system in and still broke cv's. Then they up graded cvs and broke the diff. They also had 35-37 inch tires on it maybe it's because it was a chev also. If it works for you good. I've just heard lots of stories of broken parts on a locked Ifs.

 

They always try big heavy trucks and big tires. I always wondered how well it would work on a truck like mine a regular cab and just 33's.

 

I'm not sure maybe it would be completely fine especially if you didn't have the wheels cut full lock and getting rowdy with the go pedal

 

They always used chevy's. They have weak split case diffs to begin with. My truck has 3.73's now. But I had 4.10's with 33" tsl's and never broke a cv or diff housing. I wheeled hard. Another reason fords are better.

 

^ good to know!