I was under my truck doing some work on other parts and noticed two fasteners just hanging loose on the rear drive shaft. Does anyone know what they’re for? They don’t seem to fit around anything nearby, and I haven’t noticed any problems while driving.
Those are probably for a small grease boot around the slip joint.
Looks like you’re missing the rubber boot that goes around the slip yoke. Those hose clamps should be holding it in place. The yoke is slipping in and out, so it needs grease and protection to keep dirt and debris out.
@Gale
Perfect, thanks! I’ll try to get one soon. I was already planning on replacing all the U-joints in a couple of weeks, so it might be a good time to do this too, or at least an excuse to do it earlier.
@Wilkie
If the slip joint goes bad, you’ll need to take it to a driveline shop. They’ll have to weld a new stub and balance the shaft. It cost me $900 for that plus new joints and a support bearing. Not saying yours is bad, but definitely get a new boot soon.
@Rey
No way! I can’t afford another hit like that right now. I just spent about $900 on parts for the rear hubs and differential maintenance. I’ll wait until next payday before I dive into that!
@Gale
Sounds like an unexpected Thursday night!
You definitely need to replace that grease boot and refill it. If you don’t, it’ll ruin the slip joint. Trust me, I learned the hard way.
Montana said:
You definitely need to replace that grease boot and refill it. If you don’t, it’ll ruin the slip joint. Trust me, I learned the hard way.
Wait, how do you know that? 
@Tatum
Well, the carrier bearing strap rusted in half while I was on the highway at interstate speed.
Montana said:
@Tatum
Well, the carrier bearing strap rusted in half while I was on the highway at interstate speed.
Uh oh… I see where this is going…
Montana said:
You definitely need to replace that grease boot and refill it. If you don’t, it’ll ruin the slip joint. Trust me, I learned the hard way.
Yeah, I think I’m done learning things the hard way too, haha.
You should take it to a driveline shop. They’ll fix it, balance it, and put in new center supports.