Ok guys I'm in a tough spot. I went to go get a 4 wheel alignment cause I was concerned the truck was dog tracking in the rear after I did the 2 "lift. Which it was..so I brought it to the shop I been to before and they recommended that I installed full blocks instead of stacking a 2" block on top of the factory. So I bought the blocks off them and brought it home to swap out. While I was about to remove the u bolts around the axle I ran out of room to jack the truck any higher cause my headache rack was in the way. So dummy I am I put truck in neutral and rolled It out a bit so I could jack it higher and my drive shaft fell out cause everything was pretty loose in rear end. SO we noticed the u joints on driveshaft looked rough so we changed them since it was out already. Once we got the driveshaft back in the 4 bolts holding the u-joint on the rear diff side one of them i actually over torqued and it snapped. Managed to get it out and find a replacement at a bolt store. I was sure careful tightening that one.after we bolted everything back together we noticed that the actually pumpkin on the diff was facing down a bit . Not square or straight up how they always are. Is this going to be hard on u joints now?? I was hoping the shop i was gonna take it to could straighten it out for me since I wanted a 4 wheel alignment .they did a great job on alignment truck pulls straight but the diff was still tilted down a smidgen. A week later I went for highway cruise and seemed fine. Today I went on highway again and started hearing a loud noise underneath
it got lounder then bang! Driveshaft fell out!! It slipped out of the yoke side of the rear diff. The clamps were still on the yoke. How the hell does this happen!!!?? Is it because this rear diff is tilted down a bit? Or clamps weren't super tight ? Help please I can't afford to keep going back to the shop.

 

Diff is tilted down and back normally. You can't really change that since there's a flat spot where the blocks sit! Time for new bolts and/or yoke.

 

Many things wrong here. You don't need a 4 wheel alignment because you can't align the rear. That's for newer vehicles.

The pumpkin tilting down is fine (depending on how much) as the blocks probably changed the pinion angle a little which is needed when lifting a truck.

The u joint feeling it could have been because it was the wrong u joint

 

which bolts ? Have brand new u bolts and blocks around diff already. Unless your talking the 4 little 1/4" bolts on the yoke?

 

I'll send a pic this weekend. Its not crazy tilt but its defiantly enough to notice. I think your right the new blocks changed the angle. But if the diff is tilted down even a little bit down is down enough at that angle for the u joint to pop out? Maybe they did sell me wrong u joint everything felt tight..or maybe the little bolts holding it in should be replaced...I need to find torque spec on those little guys

 

The blocks are not perfectly rectangular. They are going to be sloped on one edge, so the pinion should be angled UP toward the t-case. Did you install them in the correct orientation?

I don't know of any vehicle that has the diff pointed down..... that would do really bad things to driveline angles, promote rapid u-joint wear, and quite likely give you a nice vibration as well.......

 

Yes the high side of the block is facing the diff. The tapered shorter side is facing the front of truck. I know it can't be good for the truck. That's why I'm wondering why the u joint decided to pop out because of the slight angle of diff. That or clasps on u joint werent very snug.

 

I think what he means is the pinion iss facing up towards the t case but the diff cover is facing down more

 

Yes. I'll send a picture of the diff cover when I get home from work. I bought a new u joint and new straps and bolts for it as well. Thinking of popping it back in but I'm kinda scared its gonna do the same thing and pop out again because of the angle that the diff is sitting at.

 

The pinion should be pointing more or less at the t-case. If it is, that's fine. Put the shaft back in, tighten the bolts good, maybe run it on jack stands a bit?