Rhythmic Thumping

I have noticed a subtle thumping on my 2011 TRD Sport. It has a kind of rhythm to it so I am thinking it's something in wheel or axel. It seems to definitely be coming from the front end. I have checked my tires and there is nothing in them, just to eliminate that. It is most noticeable around 35-50mph. Anyone have any clues as to what it might be?

 

Does the thumping occur consistently on all road surfaces? Do you have a rock or other object stuck in tire tread?

 

The mice in your undercarriage are hosting another rave?

 

I used to love this prank. Take an extra long zip tie and wrap it around the upper drive shaft.

 

Nothing in the tread and it happens on all roads, no matter the surface.

 

Radio on?

 

Does the thumping varies with speed?

 

Or vary with engine speed?

 

Check the tires for a separated belt or a knot or bulge.

 

Would center bearing cause this???

 

Check tires, check wheel bearings

 

It does vary with speed. The cadence slows when I slow and speeds up when I go faster.

how do I check the wheel bearings?

 

Lift the front wheels off the ground. Grab the wheel at 12 and 6 and see if there is play. Also spin the wheel by hand as fast as you can while holding the steering knuckle with your other hand. If the bearing is noisy you will hear and feel vibrations through your hand. It should be whisper quiet and smooth. Compare side to side. If one side is louder/rougher than the other, the loud side is the bad bearing

 

Intake has a resonator that will air thump.
Especially with CAIs
There's a thread on TW with Video of the sound from a custom Intake thumping.
Resonator
Adding an expansion chamber to the intake tube forces air coming back out of the engine to slow down to fill the cavity, thus expending a great deal of its energy and slowing the pressure wave reversion. This slowdown allows fresh air to flow toward the engine without fighting pressure reversion waves the entire way, thus aiding in cylinder filling. Since these pressure waves are essentially sound, giving them a place to expend their energy before exiting the air filter box ends up dampening the intake noise and quieting the engine. Thus, the resonator helps to make the engine paradoxically quieter and more powerful

 

Forgive me but what is a CAI?

 

Cold air intake

 

Lured by title.

 

Cold air intake

 

Start by rotating your tires criss cross. Wiggle the fronts 12 and 6 o'clock to check wheel bearings. Grease driveshafts and check UJ's.

If that isn't the culprit check:
-Front Drivers side axle shaft (google ECGS bushing)
-Steady bearing on rear driveshaft.

I just went through all this and it was the tires. 5 year old BFG KO2's 10 ply. New tires going on in the fall.

 

Ever had your alignment checked? If you have any cupping wear (which can be hard to see), even if it's minor can cause that type of noise particularly in that speed range