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Unread 11-29-2013, 10:51 AM   #1
Berzerk
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How Do I Initiate 4WD?

I haven't tried 4wd yet but I'm going off roading today. Any help on how to initiate 4wd on a 1991 jeep yj?

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Unread 11-29-2013, 10:52 AM   #2
nicholasburr
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2008 JK Wrangler 
 
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shift the transfer case to either 4hi or 4lo, consult your owners manual. neutrals probably required. the t case shifter is the smaller gearshift near your main auto or manual transmission shifter.
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Unread 11-29-2013, 11:13 AM   #3
imstillatwork
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1993 YJ Wrangler 
 
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A np231 can be shifted between 2wd HI and 4wd HI at low speeds (30mph and under or so) without stopping.

To shift into and out of 4wd LO you must stop.
1) Stop.
2) Transmission in N (5spd, not sure on auto)
3) Shift transfer case into 4lo (pull back, right, back all the way)
4) Transmission in gear and drive away.

Get out of 4wd LO
1) Stop
2) trans in N
3) transfer case in 4wd HI or 2wd HI
3) trans in gear and drive away

Change between 2wd and 4wd HI under 30mph
1) clutch in
2) transfer case in 4wd HI (pull straight back, don't go into LO)
OR
2) transfer case in 2wd (push straight forward)
3) clutch out, keep driving.
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Unread 11-29-2013, 02:19 PM   #4
Apollo12227
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1992 YJ Wrangler 
 
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Quote:
Originally Posted by imstillatwork View Post
A np231 can be shifted between 2wd HI and 4wd HI at low speeds (30mph and under or so) without stopping.

Change between 2wd and 4wd HI under 30mph
1) clutch in
2) transfer case in 4wd HI (pull straight back, don't go into LO)
OR
2) transfer case in 2wd (push straight forward)
3) clutch out, keep driving.
The YJ NP231 transfercase can be safely engaged into 4HI at "any legal speed". This information was taken directly from the owner's manual and FSM.

You don't "technically" have to clutch either... Just as people with the tf999 auto don't have to go into neutral in order to achieve 4HI engagement safely. Your only going to put wear on the np231's syncro gear if your heavy on the gas/loading the drivetrain heavily while trying to engage it.



Here is a thread on the topic: Let off the gas, reach down, pull.... Thats all you need to do for 4hi. 4lo is done as you described.

http://www.jeepforum.com/forum/f12/w...ft-fly-949926/
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Unread 11-29-2013, 03:14 PM   #5
Jeepsr4me
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Can be put in 4x4 Hi at ANY speed... heheheheh I did it at over 80 in the middle of the desert.
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Unread 11-29-2013, 03:26 PM   #6
Mean Max
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Quote:
Originally Posted by Apollo12227 View Post

The YJ NP231 transfercase can be safely engaged into 4HI at "any legal speed". This information was taken directly from the owner's manual and FSM.

You don't "technically" have to clutch either... Just as people with the tf999 auto don't have to go into neutral in order to achieve 4HI engagement safely. Your only going to put wear on the np231's syncro gear if your heavy on the gas/loading the drivetrain heavily while trying to engage it.

Here is a thread on the topic: Let off the gas, reach down, pull.... Thats all you need to do for 4hi. 4lo is done as you described.

http://www.jeepforum.com/forum/f12/w...ft-fly-949926/
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No one here knows what they are talking about. You should try Pirate 4x4 they will be happy to help you.

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Unread 11-29-2013, 10:11 PM   #7
imstillatwork
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1993 YJ Wrangler 
 
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Location: Oregon Coast, Oregon
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Quote:
Originally Posted by Apollo12227 View Post
The YJ NP231 transfercase can be safely engaged into 4HI at "any legal speed". This information was taken directly from the owner's manual and FSM.

You don't "technically" have to clutch either... Just as people with the tf999 auto don't have to go into neutral in order to achieve 4HI engagement safely. Your only going to put wear on the np231's syncro gear if your heavy on the gas/loading the drivetrain heavily while trying to engage it.
Ahhh!, thanks, mine does act up a bit over 30, and without clutch... thanks for the good info!
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