I was on interstate this morning and suddenly felt hard vibration so I quickly let off gas and slowed down. Then within a few seconds a really loud banging. Found the drive shaft came out of mounting bracket where u-joint connects. Anyway I pulled out the drive shaft out of transfer case and put in 4 hi so I could limp to work. I did end up loosing a qt of transmission fluid out of transfer case.

After further inspection I saw the u-joints brackets and u-joints mounting bolts were still attached. What would cause this to happen? The u-joints are several years old, but seemed ok. I just had them out off when I replaced my transfer case.

How can I tell if the drive shaft is still ok? And is there any thing else I should look for when I put this back together. Obviously I am putting in a new u joint.

 

How long ago did you have the driveshaft out? One thing could be that you had one of the caps caught on the edge of the yoke and it just worked itself loose. Or you didn't have the bolts tightened down enough. Or there could have been nothing wrong with what you did when you put the shaft back in. If you have the bolts and straps instead of u-bolts then you're finding out one of the big problems with u-joint straps.
You'll want to check your drive line out and see if you have any dents or scrapes on it. Also look to see if any or the balancing weights were knocked off. If it all looks good then I would install a new u-joint and new straps and bolts. Take it for a drive and see if you feel any vibrations. If you do then pull the rear shaft back out and take it to a driveline shop and have them balance it. The one thing I can say is you're lucky that it dropped out from the rear instead of the front. I have seen vehicles lifted up into the air when the front of the rear drive line drops and catches on a crack or rib. Good luck with it and take your time. Also try and get a u-joint that has a grease fitting so that you can grease it once you install it and then every 5,000 miles after that.

 

What he said, but I would replace the u-joint bolts and straps with new ones as you have no idea how they have been stressed. They are cheap I think $15 for the kit. Make sure the yoke that fits into the xcase has no burrs on it (from dragging on the ground) and make sure it's clean before you install it.

 

I will definitely replace straps and bolts, when I change the u joint out. The drive shaft looks straight with no dents or gouges, Only a very tiny mark where it hit pavement, but not deep. Like Wildman4x4nut said, I was lucky as it could of been a lot worse.
Thanks everyone and Happy Holidays!

 

Once you have it all back together again there is a run out test for the DS in the fsm you might have a look at the procedure, see if it's something you want to check out or not.