Ever 3 or4 miles i get a clunky grinding sound in my rearend of my truck

Probably something wearing out back there.

Sounds like your rear end may be going out, check your diff.

sounds like the torque converter to me maybe a loose flywheel .

could be trans or rearend.

That noise sounds to me like a Ball Joint problem. I would check to see if you have fittings to grease the front suspention.

Good luck, Allen

have the rear differential and rear axle checked.

Have you checked the fluid level? If not, it could indicate it's too low. This isn't a 'normal' sound, but hopefully topping off the gear oil in the rearend will quiet it down.

check you tire wall, trunk, rear drive shaft. anything rubing?
if not, drive shaft need to replace.

well i had the same problem everyone told me the clutches in the rearend were sticking making it stick in positive traction (only your passanger side rear wheel pulls unless you start spinning then a type of clutch engages the other side so you have traction then when you stop spinning it disengages it should never be engaged if your on pavment) now you can do what i did listen to everyone when they tell you its normal or you can take it to someone with experience now and save yourself some money cause it will start popping then it will get some viberation then next it will break the clutches and when that happens you will have to replace the pinion,ring,and the spider gears as well as the clutches.make sure you have pleanty oil in rearend if you dont add the limited slip conditioner it might free clutches up but if i had it to do over id put it in the shop or stop driving it before i broke something hope this helped

CHECK YOUR UNIVERSAILS COULD BE WORN OR DRY U NEED TO PULL OUT THE SHAFT TO CHECK PROPLEY CHECK FOR STIFFNESS AND NOTCHEY MOVEMENT