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  #31  
Old September 8th, 2017, 14:57
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TRCM TRCM is offline
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Re: Front driveshaft spins in 2wd with unlocked hubs

Ok...according to the grimmreaper site, 35" tires, AW4 trans, NP231 tcase, you should be doing 81 mph @ 3000 rpm down the highway

IF you stay in 3rd gear, it should be 61 mph @ 3000 rpm


65 mph with those tires & gears should be 2400 rpm, not 3000............

Does you trans actually go into lockup & OD anymore ??

I know I had issues with mine in the past, and it didn't lockup or stay in OD, and even with 31's, I was spinning 2400 @ 65 mph
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  #32  
Old December 28th, 2017, 09:46
Desert4x4 Desert4x4 is offline
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Re: Front driveshaft spins in 2wd with unlocked hubs

Hmm so the case has been making bad noises. Now when I try to spin either drive shaft in neutral or 2wd it tries to spin the other. There seems to be a lot of resistance when trying to spin the front shaft. Are there bearings that allow the chain sprocket to freewheel on the main shaft?
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  #33  
Old December 28th, 2017, 09:46
Desert4x4 Desert4x4 is offline
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Re: Front driveshaft spins in 2wd with unlocked hubs

Oh and does the Np231 have a better design with the chain sprocket ?
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  #34  
Old December 28th, 2017, 20:15
Jim Malcolm Jim Malcolm is offline
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Re: Front driveshaft spins in 2wd with unlocked hubs

There are needle bearings between the chain sprocket and the main shaft. The 231 uses caged needle bearings while the 242 uses loose bearings. I've never read anything indicating one being better than the other in this regard.
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  #35  
Old December 29th, 2017, 06:23
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Re: Front driveshaft spins in 2wd with unlocked hubs

The chain is always engaged with the sprockets. The front output sprocket is fixed to the front output shaft. The sprocket on the main shaft moves around as you engage the different modes--2WD the sprocket is disengaged and freespins on the shaft (needle bearings), FT/AWD it engages the planetary differential and power is distributed to the front or rear as needed, PT/4WD it locks the planetary differential and forces the front and rear to spin at the same speed.
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  #36  
Old December 29th, 2017, 12:02
Desert4x4 Desert4x4 is offline
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Re: Front driveshaft spins in 2wd with unlocked hubs

Hmm thanks.

Maybe these cases are not designed to be operated with disconnected front hubs?
Maybe the needles bearings can't handle that much rpm?
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  #37  
Old December 29th, 2017, 16:13
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Re: Front driveshaft spins in 2wd with unlocked hubs

Quote:
Originally Posted by Desert4x4 View Post
Hmm thanks.

Maybe these cases are not designed to be operated with disconnected front hubs?
Maybe the needles bearings can't handle that much rpm?
HUh ?????

RPM is no different than if you are actually IN 4wd high....................
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  #38  
Old December 29th, 2017, 16:25
Desert4x4 Desert4x4 is offline
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Re: Front driveshaft spins in 2wd with unlocked hubs

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Originally Posted by TRCM View Post
HUh ?????

RPM is no different than if you are actually IN 4wd high....................
Front driveshaft not spinning, main shaft in transfer case spinning. Arn't the needle bearings going to spin as the chain sprocket freewheels on the main shaft?
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  #39  
Old December 29th, 2017, 19:02
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Re: Front driveshaft spins in 2wd with unlocked hubs

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Originally Posted by Desert4x4 View Post
Front driveshaft not spinning, main shaft in transfer case spinning. Arn't the needle bearings going to spin as the chain sprocket freewheels on the main shaft?
They do that all the time when not in 4wd......as long as you have the correct amount of fluid in the tcase, it 'll be ok.

It's no different than being in 2wd and doing a power brake maneuver on dirt or snow or ice where the rear wheels are churning away and the front wheels are locked by the brakes.
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