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Renix NP 231 problem

Old Aug 5, 2016 | 06:29 PM
  #1  
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From: Woodstock, GA, originally from S. CA.
Year: 1987 149k, original owner
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Engine: 4.0
Default Renix NP 231 problem

87, AW-4, 3" Rancho lift(1992) Dana 44 with tru-trac and 4.56 gears. 31" 149k miles.

Today when starting from a stop, I heard a metallic type sound as I accelerated. It lasted a couple of seconds, then went away. If I accelerate slowly I don't hear it, but apply throttle at about 5 mph and it appears, then goes away as I accelerate.
The. noise is in the front half of the Jeep. No problems at any other speed, full throttle etc.


On a whim, I shifted into 4 hi from a stop, accelerated mildly and all kinds of AWFUL noise from the transfer case. It went back into 2 drive no problem.

This is my daily driver, no off-road use in the last 10 years. Fluid is full, and pink in color.

I don't have the skill or time to rebuild it if that is what's needed. I'm in metro Atlanta.

Give some opinions and options. THANKS!
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Old Aug 6, 2016 | 08:54 AM
  #2  
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From: Prescott, Az
Year: 1990
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Originally Posted by GregGA
87, AW-4, 3" Rancho lift(1992) Dana 44 with tru-trac and 4.56 gears. 31" 149k miles.

Today when starting from a stop, I heard a metallic type sound as I accelerated. It lasted a couple of seconds, then went away. If I accelerate slowly I don't hear it, but apply throttle at about 5 mph and it appears, then goes away as I accelerate.
The. noise is in the front half of the Jeep. No problems at any other speed, full throttle etc.


On a whim, I shifted into 4 hi from a stop, accelerated mildly and all kinds of AWFUL noise from the transfer case. It went back into 2 drive no problem.

This is my daily driver, no off-road use in the last 10 years. Fluid is full, and pink in color.

I don't have the skill or time to rebuild it if that is what's needed. I'm in metro Atlanta.

Give some opinions and options. THANKS!
check the clearances here:
Attached Thumbnails Renix NP 231 problem-transmission-mount-bracket.jpg  
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Old Aug 6, 2016 | 01:24 PM
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From: Woodstock, GA, originally from S. CA.
Year: 1987 149k, original owner
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Engine: 4.0
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All clearances good. Trans mount and bolts ok. Put it in 4wd, worked fine!?

I still have the brief noise, but will search some more. Thanks Cruiser.
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Old Aug 6, 2016 | 03:13 PM
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Maybe drain the fluid into a clean container and check for particles?

Do you still have the original vacuum disconnect on the front axle?
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Old Aug 6, 2016 | 04:33 PM
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From: Woodstock, GA, originally from S. CA.
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Engine: 4.0
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Originally Posted by cruiser54
Maybe drain the fluid into a clean container and check for particles?

Do you still have the original vacuum disconnect on the front axle?
Will do. Yes, I still have the vacuum disconnect. Did you write. a tip on how to eliminate the vacuum disconnect?

I found another thread where a guy had a similar noise problem, but never solved it. I sent him a PM for an update.
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Old Aug 6, 2016 | 06:25 PM
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Originally Posted by GregGA
Will do. Yes, I still have the vacuum disconnect. Did you write. a tip on how to eliminate the vacuum disconnect?

I found another thread where a guy had a similar noise problem, but never solved it. I sent him a PM for an update.
Not written by me, but worth doing. I do it on every CAD axle I work on.

Takes 20 minutes.

Take a peek in there and see if the sliding gear is ground up or the fork is bent. 4 bolts. Super easy.

https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/
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Old Aug 6, 2016 | 06:53 PM
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it sounds to me like you may have a bad case of the angry sparrows.

time to rebuild your front drive shaft. particularly the centering ball/yoke.
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Old Aug 6, 2016 | 08:13 PM
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From: Woodstock, GA, originally from S. CA.
Year: 1987 149k, original owner
Model: Cherokee
Engine: 4.0
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Originally Posted by cruiser54
Not written by me, but worth doing. I do it on every CAD axle I work on.

Takes 20 minutes.

Take a peek in there and see if the sliding gear is ground up or the fork is bent. 4 bolts. Super easy.

https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/
Cool. Thank you. I'll do it next weekend.
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Old Aug 6, 2016 | 08:14 PM
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Originally Posted by caged
it sounds to me like you may have a bad case of the angry sparrows.

time to rebuild your front drive shaft. particularly the centering ball/yoke.
Excellent idea. at the very least, drop the transfer case end of the front driveshaft and check it out. Perhaps lube it if it's not loose?
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