Increased noise/vibration at specific RPM (1 Viewer)

[69 Pigboy]

I’ve started to get increased noise and vibration at 2000 to 2500 RPM. It’s most pronounced in third gear at around 40 mph but also appears again at the same RPM range around 60 mph. I can feel it in the gas pedal and steering wheel. It’s tied to acceleration so it’s more noticiable when I’m going uphill and the engine is working harder. It stops as soon as I take my foot off the gas.

I’ve been putting some hard miles on the rig lately with lots of very rough roads with washboard and potholes so the likelihood of something having loosened up is high.

Thoughts?

 

[LandLocked93]

Given your recent uptick in off-road travel, have you greased the u/j's and slip joint recently?
I had the same issue just after a tranny rebuild and the mechs put the shafts in backwards. Before it was figured out, I could grease the slip joint to compression (highly not recommended) and the noise would go away for a bit.
Much better that the shafts are in correctly. No issues since.

 

[PappyVan20]

I just had my rear drive shaft rebalanced because the truck was vibrating in 4th once I hit like 50MPH. It fixed that particular permanent vibration, but now there is a regular (not always) grinding/vibration noise as I get into 4th and travel between 40-60 MPH. Sound is much different and as a non mechanic, sounds like grinding gears in the transfer case area.

I’ve been told not to worry about it as this is “common”, but have sixth sense that maybe it’s not a good thing.

I think I may just need to get it to another 4X4 shop. Any thoughts? I‘m not sure I can capture sound in recording.