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Differential or Transfer case?

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Old May 25, 2025 | 08:23 PM
  #1  
Tampadoc's Avatar
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Differential or Transfer case?

Either my differential or my transfer case is going out and I can't tell which. Getting the telltale "clunk" and vibration and hum at certain speeds. What's a good way to diagnose which is going?
 
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Old May 25, 2025 | 08:48 PM
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Either use a ChassisEar, or get it up on stands and use a stethoscope..
 
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Old May 30, 2025 | 07:54 AM
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Cause for the telltale "clunk" is the propeller shaft splines need to be greased.
 
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Old May 30, 2025 | 10:56 AM
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Originally Posted by Vintage Chief
Cause for the telltale "clunk" is the propeller shaft splines need to be greased.
I would agree with this, unless it has already been addressed and isn't changing the sound.

To OP - check your fluids before you presume something is going out. Make sure you aren't low, make sure there's no excessive metal shavings in the fluids, etc.
 
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Old May 30, 2025 | 11:33 AM
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I'd check u joints as well...
 
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Old May 30, 2025 | 01:38 PM
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If it's a "clunk", it begins gradually over several weeks to a month - gets a little progressively worse, but quite noticeable when accelerating from a stop. I've re-greased the splines twice in 200K miles. This time I also did a center carrier bearing R&R.

Propeller Shaft Center Carrier Bearing
 
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