Hey guys lately when I go to take off at a red light it feels like something slides in my bed at hits the tailgate what could it be? Truck has a new rear end too. Thanks in advance, Clay.

 

Got drunk and threw a full can of beer in the back thinking it was empty only to have snowed on it so you can't see it and that's what rolls back and forth? I speak from experience.. I could not for the life of me figure out the sound from my little Toyota. Turns out it was just my bud riding in the bed.. But then I went from about a 15 mph roll straight into park and I think my u-joint did go bad right after that

 

Could be the u-joint. Mine would squeak but didn't really clunk. But a clunk is usually a good sign of a bad u-joint. Get under the truck and start checking. You'll want to try and rotate the drive shaft back and forth, and up and down and look for play. Lot's of how to video's on youtube. Wouldn't be a bad idea to check the fluid in the rear as well. Did you replace the rear yourself or have a shop do it?

Here is my video and what my u-joint looked like.

 

Had a shop replace it and thanks for the help

 

Another thing to look at is the slip joint in the driveshaft. If the lubrication is missing the slip joint will bind up when you put power to the wheels.

 

DAMN! I have never seen one that loose. holly hell

 

Me either! That was about 210,000 miles

 

I've seen them worse. As in, no needle bearings left and wearing into the caps.