NP 231 transfer case stuck
#1
Thread Starter
Junior Member
Joined: Jun 2011
Posts: 69
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From: Chickamauga, GA
Year: 1990
Model: Cherokee
Engine: 4.0L I6
NP 231 transfer case stuck
Hey everyone. I recently had my jeep up on a lift to put in a new exhaust system and while it was up, decided to install the front drive shaft (it was laying in the back seat when i bought the jeep). The 4WD shifter was in 2HI but the transfer case acted like it was locked in 4HI/4LO. We thought that when the previous owner had the TC out, he may have hooked the shifter up backwards but reversing it had no effect.
tl;dr
Have any of you had the TC lock itself in 4WD and not left go?
Also, how hard is it to change the rear seal on the TC?
tl;dr
Have any of you had the TC lock itself in 4WD and not left go?
Also, how hard is it to change the rear seal on the TC?
#2
CF Veteran
Joined: Aug 2011
Posts: 10,489
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From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Not much experience with transfer cases, but I've had shifter forks break twice. If the lever moves but nothing changes I might suspect that.
(once in a Toyota trans, the other was the Jeep 4WD "disco" in the axle.)
(once in a Toyota trans, the other was the Jeep 4WD "disco" in the axle.)
#3
Thread Starter
Junior Member
Joined: Jun 2011
Posts: 69
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From: Chickamauga, GA
Year: 1990
Model: Cherokee
Engine: 4.0L I6
Thanks for the info DFlintstone. Unfortunately, the shifter doesn't move at all. Even after disconnecting the linkage from the lever on the TC, the lever wouldn't budge. I figure I need to drop the TC, crack it open, and take a peek inside.
#5
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
I assume when "we" put it in reverse and back up to get it out of 4WD, that's just to relieve any binding with the wheels/driveline's. Nothing to do with the case guts themselves. Still, I might try rotating it backwards.....
#6
Thread Starter
Junior Member
Joined: Jun 2011
Posts: 69
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From: Chickamauga, GA
Year: 1990
Model: Cherokee
Engine: 4.0L I6
I honestly dont know, once I realized that the TC was stuck in 4WD, I took the front driveshaft back off. I'll check that out when I get home.
#7
Newbie
Joined: Mar 2010
Posts: 24
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From: Bamberg Germany
Year: 2000
Model: Cherokee
Engine: 4.0, Nothing better
i have had an experiance with hooking up the linkage on the TC backwards while putting a tranny in. It looked it into 4 wheel drive and wouldnt come out. Maybe if you can check another jeep to compare the linkage? If the previous owner pulled the front drive shaft he might have known something that you dont. Maybe even check your fluid to see if you can find any contaminants.
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#9
Thread Starter
Junior Member
Joined: Jun 2011
Posts: 69
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From: Chickamauga, GA
Year: 1990
Model: Cherokee
Engine: 4.0L I6
When we had it on the lift, it was almost bone dry. It had just a little in the bottom of the case so we filled it up but the rear seal is leaking pretty heavily. Im going to pull it out when I get home from this work trip and take a look.
#12
Thread Starter
Junior Member
Joined: Jun 2011
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From: Chickamauga, GA
Year: 1990
Model: Cherokee
Engine: 4.0L I6
I pulled the TC out yesterday and as soon as I cracked the seal between it and the transmission, about a cup of water ran out. After I got it on the table, i turned the front yoke by hand and found 2 things: (1) the TC sounds like it has a handful of rocks in with the gears and (2) the rear output shaft has a lope to it (i.e., it moves up and down when it turns). I'm going to crack it open tonight and see what the hell is going on inside. I'll take pics of what I find (because we all love to cringe at mechanical carnage).
Last edited by benstoker; 03-05-2012 at 11:20 AM. Reason: typos
#13
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
#14
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Joined: Jan 2012
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From: Smithfield, VA
Year: 1997
Model: Cherokee
Engine: 4.0
Looking forward to those pics.
That reminded me of a friend that use to race carts. He had a nitro briggs 5hp literally explode one night. He gathered up all the pieces he could find and eventually glued them to a piece of plyboard. It was one cool looking "exploded" view of a briggs & stratton.
That reminded me of a friend that use to race carts. He had a nitro briggs 5hp literally explode one night. He gathered up all the pieces he could find and eventually glued them to a piece of plyboard. It was one cool looking "exploded" view of a briggs & stratton.
Last edited by gpeade; 03-06-2012 at 12:03 PM.
#15
Thread Starter
Junior Member
Joined: Jun 2011
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From: Chickamauga, GA
Year: 1990
Model: Cherokee
Engine: 4.0L I6
Sorry for the delay. Here are the pics so far:
Input shaft bearing housing. Aluminum rusting on it from where there was a cup of water between it and the transmission.
Front of the TC with the input shaft bearing housing off.
Nasty rust paste coated the input shaft bearing.
Front half of the TC. Nasty junk on the clean-out magnet and the gear oil inside had the consistency of mud.
Detent plug. This little sucker is keeping me from shifting out of 4WD.
Detent plug holding the sector from moving (WTF?)
Detent plug spring and pin removed.
Input shaft bearing housing. Aluminum rusting on it from where there was a cup of water between it and the transmission.
Front of the TC with the input shaft bearing housing off.
Nasty rust paste coated the input shaft bearing.
Front half of the TC. Nasty junk on the clean-out magnet and the gear oil inside had the consistency of mud.
Detent plug. This little sucker is keeping me from shifting out of 4WD.
Detent plug holding the sector from moving (WTF?)
Detent plug spring and pin removed.