Hey Guys, well my rear end is going out on my 06 fx4. i have the 9.75" rear end with 3:73 gears, does anyone know whats a good parts to replace with?

 

What is going bad? The ring gear and pinion? Carrier bearings? Pinion bearings?? These things aren't rocket surgery you know.

 

Give us a good description of the noise. Its probably a bearing going out, or maybe even just the factory posi clutches starting to chatter/squawk. Actual gear failures are rare. To replace the bearings and clutches (if equipped with a posi) will typically run about $500 at a good shop. For bearings, I buy Timken almost exclusively. If it needs clutches, get them from Ford.

 

What's the mileage on said bad rear end..? Has it ever been serviced .. ?

 

Might just need a fluid change if it's making minor noises or "skipping" during turns. Like Tech mentioned, mileage and service history?

 

I'm watching this with interest. My 04 with 150k is doing the same thing and I have the same rear as you.

 

Truck has 140k, Serviced rear diff and trans regularly. a ton of metal shavings in fluid.

 

the pinion seal went out a few years ago. I changed that, it started a slow leak about a month ago, and the grinding noise has gotten progressivly worse. had 2 different mechanics listen to it. one from ford. both said needs a rebuild gears and bearings. its not slipping, just makes a metal on metal grinding noise.