1981 CJ7 Drivetrain Noise Under Light Acceleration

[tomcatzilla]

Hi there, 

my CJ7 from 1981, with AMC258, AMC20, Dana 300 and SR4 transmission sadly makes noise on low acceleration. 

I can‘t whether the noise is coming from axle or transmission. The noise is noticible on low acceleration only. If I put more power on it or get off from the acceleration padle, the noise is gone. 
In addition, a slight vibration can be felt on the gear knob as soon as the noise can be heard. The jeep was rebuilt by me three years ago. the cardan shaft and the bearings in the rear and front axle are new. i didn't dare to work on the transmission and transfer case. but at first sight I couldn't see any worn or loosen parts. the differential in the rear axle is also new. Today i checked if i can find anything Worn or loose, but there is nothing 😞
 

here is the link to YouTube:

 

 

thanks for your help! 
 

best wishes from germany!

your US Jeep fan 

Marius

 

[Moses Ludel]

Hello, Marius...Beyond the noise, a very good sounding CJ-7 Jeep...First, do you have free wheeling hubs at the front axle?  Make sure both hubs are on "Free".  With the vehicle safely parked and engine shut off, make sure that the front driveshaft turns freely with the hubs set on "Free" and transfer case in 2WD.  Listen for any noises as you rotate the front driveshaft.

The SR4 is a light duty transmission, and the Dana 300 is a rugged transfer case.  Let's try a few things to separate transmission noise from transfer case noise. 

Some transmission questions:

1)  If you depress the clutch pedal when you hear the noise, does the noise go away?  

2) If you get up to the noise speed and place the transmission in neutral and coast, does the noise go away?

3) Stop the Jeep and place the transmission in neutral.  Let out the clutch pedal.  Do you hear any noises?

4) At the speed you hear the noise, place the transmission in 4th gear and release the clutch pedal slowly.  Does the noise stop?

Some transfer case questions:

1)  If you hear the noise and slide the transfer case into neutral, does the noise stop immediately?  (Be sure to stop the Jeep completely before shifting the transfer case back into gear.)

2)  Do you hear any noises when the engine is under load in 4th gear?

Let me know what you find.  We will go from there.

Moses