Just about all of them...... I have what is know as "Rice Crispy Spine"......

 

It's a 2wd

 

Well, not front u-joints then.

If you jack it up, and spin the tires, can you hear the noise?

 

Ok so I have figured out what the mysterious noise is I think. I am almost sure it is coming from differential. Like maybe pinion gear? I do know that my spider gear has a couple teeth broken off it as well. I have t been able to have it confirmed but hearing the noise compared to some of the videos I have watched it is exactly the same. I have a few questions now...
1. Would it be better to replace parts or just get a whole new rear end?
2. Is it dangerous to drive my truck until I have the funds to repair?
3. How much should repairs like that cost?
4. Does it seem like I've found the correct answer?

Any and all help, suggestions, and/or advice is greatly greatly greatly appreciated. Thank you in advance!

 

If you have broken teeth in there already, it's a ticking time bomb. It may run forever and a day, it may lock up tomorrow..... It's a gamble. If you have something else to drive, leave the truck sit till you fix it.

If *all* it needs is spider gears, that's a relatively easy repair. If it needs more than that, might be cheaper just to replace the entire rear diff.....