Can you help me diagnose a "tapping" sound?

[Noodle]

I have a 2001 Jeep TJ with 60k miles and 33" Ko2s. The drive shafts have been upgraded, re-geared to 4:56, new carriers, and NP231 SYE installed. Drive train work was done over a year ago at Northridge 4x4 and has been driving great. Recently I have been hearing a "tapping" sound that seems to be synchronized with wheel speed. It's loudest when going downhill and slowing down. It still makes the same noise when in neutral. Braking does not change the sound (other than slowing wheel speed and tap) and I have inspected all of the drive shafts, brakes, and u-joints. I put the jeep on jacks and spun each tire and could not reproduce the noise.

I am stumped. Any suggestions on next steps and diagnosing the problem is appreciated.

 

[ohiopatriot]

Can you tell where it's coming from? Front, rear, left, right, center?

Rock or bolt stuck in tread?

 

[TJ2]

The cat also makes tapping sound if it is already on it's last leg.

 

[Noodle]

Can you tell where it's coming from? Front, rear, left, right, center?

Rock or bolt stuck in tread?

Not a Rock or Bolt. Sounds like front center. Its difficult to place.

 

[Stockli]

Automatic? Have you checked the bolts on your flex plate?

Sounds weird but they can work loose and you will hear a tap from the tunnel/firewall area. Also flexplate could be cracked.

Sorry this was for a Cherokee Aw4 trans not sure if it holds true on the 42rle

 

[Noodle]

Automatic? Have you checked the bolts on your flex plate?

Sounds weird but they can work loose and you will hear a tap from the tunnel/firewall area. Also flexplate could be cracked.

Sorry this was for a Cherokee Aw4 trans not sure if it holds true on the 42rle

Its a 5 speed manual.

 

[ivan cox]

Goodmorning Ladies and gents

I have the same tapping noise on my 2005 tj, we have replaced the u-joints twice, done axle bearings, greased all joints. i also have alot of up and down movement of my diff when pulling off, reversing etc. i'm now longer sure what to fix, noise is either centre or rear.

Any advice would be greatly appreciated.