Vibration under braking and acceleration

The vibration starts at 1500 rpm and disappears around 2500 rpm. When braking it does the same with the most vibration just before the engine hits idle.
Workshop jacked up the diff and ran the engine in drive but could not reproduce it this way
nor find any problems under the car.
We changed the front tires for new ones and aligned the front. There was no issue there.

What could be the problem?

 

Brake rotors warped? Assuming Lug nuts were tightened.

 

Center bearing possibly

 

No the vibration is there under acceleration as well

 

Already replaced

 

year, model, trim level of truck?

Sounds like classic axle wrap common on these trucks with their flimsy leaf springs.

 

Highly likely u-joint. I've replaced two in 200,000 miles. Exact symptoms as yours.

 

Broken leaf spring, maybe

 

Was center bearing replaced with Spicer or oem? The aftermarket CB’s are really bad. The bearing itself is not the problem, it’s the rubber they use - too pliable. If you have a lift, did you use a CB drop kit? Any half inch spacer will do.

 

Having the exact issue with my 22 trail edition with 3k miles.

 

Thank you for your replies. According workshop it is the rear u-joint. Center bearing support and other u-joint were already replaced a few years back. They should have done this one while they were at it.