OK I only get this when it my JK has sat for several hours or overnight and it is cool outside ( 55 F or colder )

I hear it when accellerating for the first 10 to 40 yards after starting the Jeep.

To describe the noise it sounds like super bad loud intermittent gas knock.

BUT it's not comming from the motor so it's not gas knock. It's is comming from the rear of the Jeep.

My guesses;

1. CV on the rear drive shaft?

2. Drum parking brake (adjuster) ?

3. Spider gears?

4. Wheel bearing?

5. something in the transfer case?

When I let off the gas it goes away while driving.

Won't do it with the rear axle lifted ( Jeep stationary) I guess cause there is no load being put on the drivetrain. This is really getting hard to diagnose.

Anyone had experience with a noise like this?

 

I have the same noise coming from the rear of mine, it lasts a little longer but I guess that maybe caused by the colder Alaskan winters. I'm heading to the dealer tomorrow so hopefully I'll have something to report.

 

sounds like your tires if warm and then they get cold it will creat a temporary flat spot and driving warms the rubber and makes them round again

 

That's a good guess but it's not the problem, usually when you get a flat spot in your tire the rides really rough and kind of obvious what's going on. this sounds allot like a clicking/grinding mechanical noise coming from the rear not the thud thud thud you get when you have a flat spot in your tires, also I don't know if you noticed this but it does get allot quieter when you're in 4wd as opposed to 2wd I have no idea why but that's just my observation.

 

Please keep us posted on what they/you find out.

THANKS !!

 

I have the same noise. Sounds like some marbles rattling. Only does it for the first minute or so in the morning. Only when accelerating. No idea what it is, but I don't think it's the engine.

 

When the noise starts push in the clutch and rev the engine.

If the noise goes away then it's not the engine and you possibly have the same problem as me.

If after pushing in the clutch and reving the engine the noise gets faster and louder then you have gas knock.

But you described the noise I have exactly as marbles rattling in a metal can at a random.

We will get to the bottom of this ! ! !

 

If I push in the clutch it goes away. The noise only happens while accelerating. I think I have the same thing you do.

 

Yep sounds like it.

And there has to be more people also.

 

Well I got nothing but stupid looks from the dealership. they heard the sound but they have no clue on what it could be. I got tired of driving the lame rental they gave me. so I just took my jk back and told them to do some research. They said I should schedule another time to bring it in, but to be honest I'm not too sure they have the capability to figure it out what it is. I guess we'll see.