Driveline or suspension noise

Some day I'm going to find the source of this noise, but so far I have been unsuccessful.  If you have an idea, hit me with it.  Pretty please.

2007 Dodge 2500 4x4 diesel automatic.

Taking off from a stop, I get a single clunk.  The noise is not always the same.  Sometimes it just sounds like a tap on the exhaust pipe with a screw driver.  Other times it's a more solid thunk and I can sort of feel it in the floor.  It is not always immediate.  Sometimes it is right a take off and other times it will wait until the 1-2 shift, but it pretty much always happens.

Things I have checked:

Front driveshaft

Front sway bar links

Track Bar bushing has been replaced, but should probably get drilled a size larger.  The hole through the bracket is a bit worn out of round.

Front shocks have been replaced

I think I have driven it with the rear driveshaft removed and it still made the noise, but I can't remember for sure.

Transmission has been rebuilt.  Made the noise before and after the rebuild.

Rear diff oil has been changed.  It was pretty crappy, but no change in the noise.

Possibilities that I haven't really checked:

Transfer case - don't know how I could determine that. Oil has been changed, but it looked fresh.

Motor or transmission mounts

Steering components - truck has a steering box brace.  I should check the mounting bolts.

Brakes - I have replaced pads and checked caliper bolts, but I haven't checked deeper than that.

Do you have any greasable joints? Like U-Joint or ball joints?

I researched similar noises for my 2016 Ram 1500 and most of the stuff I found was for your year model. 
 

Mine thunk that I heard when taking off, and felt through the pedal, turned out to be ball joints on lower control arm with no grease.

Grease driveshaft u-joints if you can. People also have had to put grease in the actual driveshaft slip yoke to fix the issue. Super easy job and very common for your truck.

I'll have to check the ball joints, but it seems like that would continue to make noises while driving beyond the one at initial take off.

I'll go through the driveshafts again.  I hadn't considered greasing the slip yoke.  Easy enough to try it.

If you power brake it, does the noise still happen? Does it happen before the truck moves or after? Does it change when the noise happens? 

Does the rate of acceleration change the noise or change when it happens?

I had a torque converter who's bolts were coming loose from the flex plate and sounded a lot like what you describe.

Toyman! said:

If you power brake it, does the noise still happen? Does it happen before the truck moves or after? Does it change when the noise happens? 

Does the rate of acceleration change the noise or change when it happens?

 

Good questions.  I haven't tried power braking.  The noise always happens in motion, sometimes right when you start moving but not always.  Sometimes it won't happen until the 1-2 shift.

It happens faster (almost immediately) if you accelerate harder.  If you take off slowly, it doesn't happen right away.

VolvoHeretic said:

I had a torque converter who's bolts were coming loose from the flex plate and sounded a lot like what you describe.

I had the transmission rebuilt almost a year ago including a new flex plate and torque converter.  It was making the noise before and after the transmission work, so I really hope that isn't the issue.

In reply to bigeyedfish :

Power braking it may help narrow it down to driveline or suspension/wheel bearings/brakes.

Hard acceleration makes me think driveline. 

Does it do it worse or differently with the 4wd engaged or less? 4 high vs 4 low?

You might check for stuff rolling around under the seats.