exploded view of np246 ?
07-21-2004, 05:30 PM
#11
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Originally Posted by LS1NOVA
I can check at work on the price, since I can buy for 10% over cost. I have a used one but it is 3 hrs away at my storage building. I would sell it for $100 shipped.
08-10-2009, 02:15 PM
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I have seen many of these with burnt up clutch packs under warranty. Pretty easy fix if its just the clutch packs. You can remove the rear half of the case and its basically right there in your face. There is also a shim that determines the preload on the clutches but usually the stock shim ends up being right. good luck
12-11-2009, 02:25 PM
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Works in Auto but not 4Hi or 4 Lo
I have seen many of these with burnt up clutch packs under warranty. Pretty easy fix if its just the clutch packs. You can remove the rear half of the case and its basically right there in your face. There is also a shim that determines the preload on the clutches but usually the stock shim ends up being right. good luck
2Hi disconnects everything else just like it's supposed to. Is there more than one clutch pack?
Thanks
Lynn P.
01-26-2010, 04:34 PM
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LS1Nova, I know this is an old thread and I found it doing a Google search, but I hope you're still around. I have a 99 NBS Silverado 1500 and the 4wd works in Auto but nothing else. A friend who is a GM tech and says that is backwards from what they normally find. We can hear and feel the motor working, the lights work at each position, no codes, just won't transfer power in anything other than Auto. The front differential actuator works as it's supposed to also.
2Hi disconnects everything else just like it's supposed to. Is there more than one clutch pack?
Thanks
Lynn P.
2Hi disconnects everything else just like it's supposed to. Is there more than one clutch pack?
Thanks
Lynn P.
03-06-2010, 11:07 PM
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Np246 transfer case
HAZE,
You are most likely blowing your clutch pack because of the Whipple. I have a 2500 Suburban 6.0L with a whipple and borla headers and exhaust. I have been through 2 of these transfer cases in the sand. The stock clutches suck! I have the same problem. No pull in the front. Very little pull I should say. In reverse i have no pull at all. Forward I have about 5 % pull. I can smell the fluid burning in the transfer case. It's gotta be the Whipple. Not many people have a whipple and when I read you post I thought I wrote it. I have the exact same problems. Did you ever find a fix?
You are most likely blowing your clutch pack because of the Whipple. I have a 2500 Suburban 6.0L with a whipple and borla headers and exhaust. I have been through 2 of these transfer cases in the sand. The stock clutches suck! I have the same problem. No pull in the front. Very little pull I should say. In reverse i have no pull at all. Forward I have about 5 % pull. I can smell the fluid burning in the transfer case. It's gotta be the Whipple. Not many people have a whipple and when I read you post I thought I wrote it. I have the exact same problems. Did you ever find a fix?
03-06-2010, 11:10 PM
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HAZE,
You are most likely blowing your clutch pack because of the Whipple. I have a 2500 Suburban 6.0L with a whipple and borla headers and exhaust. I have been through 2 of these transfer cases in the sand. The stock clutches suck! I have the same problem. No pull in the front. Very little pull I should say. In reverse i have no pull at all. Forward I have about 5 % pull. I can smell the fluid burning in the transfer case. It's gotta be the Whipple. Not many people have a whipple and when I read you post I thought I wrote it. I have the exact same problems. Did you ever find a fix?
You are most likely blowing your clutch pack because of the Whipple. I have a 2500 Suburban 6.0L with a whipple and borla headers and exhaust. I have been through 2 of these transfer cases in the sand. The stock clutches suck! I have the same problem. No pull in the front. Very little pull I should say. In reverse i have no pull at all. Forward I have about 5 % pull. I can smell the fluid burning in the transfer case. It's gotta be the Whipple. Not many people have a whipple and when I read you post I thought I wrote it. I have the exact same problems. Did you ever find a fix?
01-23-2015, 05:09 PM
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Old thread but I will chime in.
I have the exact same problem, works on auto 4x4 but not in other modes.
No error codes, no lights flashing, everything behaves as it should but for the front wheels having no torque.
Also, if get in a situation where only the rear wheels are spinning and the truck not moving (like stuck in snow), and I allow the rear wheels to spin gently, when I change from 2HI to 4HI and back, I feel a surge when the motor passes between the two modes, the cluch engages shortly.
My diagnosis, according to my research: the TRANSFER CASE MOTOR LOCK is either broken or always energized.
The purpose of this lock it to avoid the motor to slide back into the "disengaged" clutch position.
Picture of the clutch and cam:
--- from the mitchell manual----
transfer case motor lock is used to prevent the transfer case from
changing mode/gear positions or popping out of position when the vehicle
is in 2HI, 4HI, and 4LO. When the lock circuit is energized, the
transfer case encoder motor is allowed to rotate. When the transfer case
is placed 2HI, 4HI, or 4LO the motor lock circuit has no voltage
provided to it, applying the lock which assures that the transfer case
remains in the current mode/gear position. When AUTO 4WD is selected the
motor lock remains applied until an adaptive mode, torque being applied
to the front propshaft is required. During an adaptive mode the motor
lock circuit is energized, the locking mechanism is released, enabling
the encoder motor to turn and apply torque to the front propshaft.
--------------------------------
So if the lock mechanism is physically broken, the back tension on the cluch will back off the motor, except in auto 4x4 when the motor is always applying torque on and off when needed.
Also, if the TCCM is defective, it could energize the lock mechanism at all times, creating the same problem.
I will take some readings and go from there, I'll keep you posted.
I have the exact same problem, works on auto 4x4 but not in other modes.
No error codes, no lights flashing, everything behaves as it should but for the front wheels having no torque.
Also, if get in a situation where only the rear wheels are spinning and the truck not moving (like stuck in snow), and I allow the rear wheels to spin gently, when I change from 2HI to 4HI and back, I feel a surge when the motor passes between the two modes, the cluch engages shortly.
My diagnosis, according to my research: the TRANSFER CASE MOTOR LOCK is either broken or always energized.
The purpose of this lock it to avoid the motor to slide back into the "disengaged" clutch position.
Picture of the clutch and cam:
--- from the mitchell manual----
transfer case motor lock is used to prevent the transfer case from
changing mode/gear positions or popping out of position when the vehicle
is in 2HI, 4HI, and 4LO. When the lock circuit is energized, the
transfer case encoder motor is allowed to rotate. When the transfer case
is placed 2HI, 4HI, or 4LO the motor lock circuit has no voltage
provided to it, applying the lock which assures that the transfer case
remains in the current mode/gear position. When AUTO 4WD is selected the
motor lock remains applied until an adaptive mode, torque being applied
to the front propshaft is required. During an adaptive mode the motor
lock circuit is energized, the locking mechanism is released, enabling
the encoder motor to turn and apply torque to the front propshaft.
--------------------------------
So if the lock mechanism is physically broken, the back tension on the cluch will back off the motor, except in auto 4x4 when the motor is always applying torque on and off when needed.
Also, if the TCCM is defective, it could energize the lock mechanism at all times, creating the same problem.
I will take some readings and go from there, I'll keep you posted.
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