Backend Seized Up. Is It Transfer Case Or Transmission?

Transfer case is bad. My first guess. If the transmission were bad it wouldn't move at any position. Is there any noise? You have 4 possibilities, Front and rear differentials, transfer case, and the transmission.

it sounds like the transfer case is in neutral good test start truck place trans in reverse slowly try to place back in park if it makes any noise then the output shaft of transmission is turning then problem is in transfer case move that lever back & forth several times this might get it working again

Transfer Case - Electronic Shift on the Fly (ESOF) Features A rotary switch allows the vehicle operator to choose between 2WD, 4H, and 4L modes of 4x4 operation.
The generic electronic module (GEM) controls the operation of the 4x4 system.
The output shaft speed (OSS), mounted in the rear of the transfer case, informs the GEM of the vehicle speed.
The shift motor sense plate, an integral part of the electronic shift motor, informs the GEM to the positions of the transfer case (go to Table 4).
The transmission range sensor is located on the LH side of the transmission; this sensor informs the GEM when the transmission is in the NEUTRAL position.
The electronic shift motor, mounted externally at the rear of the transfer case, drives a rotary cam which moves the mode fork and range fork within the transfer case to select between the 2WD, 4H, and 4L positions.
The 4x4/4x2 vacuum solenoids are attached to the upper RH side of the engine compartment, and alternately route vacuum to the vacuum motor which engages/disengages the center axle disconnect collar in the front axle assembly.
The 4x4 shift motor relay is a module containing two relays. Under the control of the GEM, the 4x4 shift motor relay shifts the transfer case shift motor between the 2WD, 4H, and 4L modes.
The transfer case clutch relay is an electromechanical relay used to activate the transfer case clutch within the transfer case.


Your best bet , take it to a qualified repair shop !

P1804 Transmission 4-Wheel Drive High Indicator Circuit Failure GEM REFER to Section 413-01A . P1806 Transmission 4-Wheel Drive High Indicator Short Circuit to Battery GEM REFER to Section 413-01A . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure GEM REFER to the Symptom Chart. P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground GEM REFER to the Symptom Chart. P1820 Transmission Transfer Case Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test A . P1822 Transmission Transfer Case Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test A . P1824 Transmission 4-Wheel Drive Clutch Relay Circuit Failure GEM GO to Pinpoint Test E . P1826 Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Battery GEM GO to Pinpoint Test E . P1828 Transmission Transfer Case Counter Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test A . P1830 Transmission Transfer Case Counter Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test A . P1832 Transmission Transfer Case Differential Lock-Up Solenoid Circuit Failure GEM GO to Pinpoint Test C . P1834 Transmission Transfer Case Differential Lock-Up Solenoid Short Circuit to Battery GEM GO to Pinpoint Test C . P1838 Transmission Transfer Case Shift Motor Circuit Failure GEM REFER to the Symptom Chart. P1846 Transmission Transfer Case Contact Plate 'A' Circuit Failure GEM REFER to the Symptom Chart. P1850 Transmission Transfer Case Contact Plate 'B' Circuit Failure GEM REFER to the Symptom Chart. P1854 Transmission Transfer Case Contact Plate 'C' Circuit Failure GEM REFER to the Symptom Chart. P1858 Transmission Transfer Case Contact Plate 'D' Circuit Failure GEM REFER to the Symptom Chart. P1866 Transmission Transfer Case System Concern - Servicing Required GEM REFER to the Symptom Chart. P1867 Transmission Transfer Case Contact Plate General Circuit Failure GEM REFER to the Symptom Chart. P1876 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Failure GEM GO to Pinpoint Test C . P1877 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Short to Battery GEM GO to Pinpoint Test C . P1891 Transmission Transfer Case Contact Plate Ground Return Open Circuit GEM REFER to the Symptom Chart.

Been there done that, I have same problem ,its the transmission, Why if it was the transfer case,look at the design it couple the drive shaft ,there a gear and chain attatched by a gear drives the front drive differential,You have a transmission failure

The 4X4 system on your vehicle is computer controlled , GEM module . generic electronic module . The four wheel drive mode switch is a low voltage input to the GEM module . The GEM energizes relay's to control the mode as depicted by input from the mode switch an torque on demand relay an someother inputs . Probably has DTC - diagnostic trouble codes stored in the GEM module .
Transfer Case -Automatic Four-Wheel Drive (A4WD) The automatic 4-wheel drive transfer case system consists of the following:

• automatic 4WD indicator light
• brake pedal position (BPP) switch
• torque on demand (TOD) relay
• front output shaft speed sensor
• generic electronic module (GEM)
• 4WD high indicator light
• 4WD low indicator light
• 4WD mode switch
• rear output shaft speed sensor
• shift position sensor
• throttle position output (TPO) from the powertrain control module (PCM)
• transmission range sensor P1804 Transmission 4-Wheel Drive High Indicator Circuit Failure GEM REFER to Section 413-01 . P1806 Transmission 4-Wheel Drive High Indicator Short Circuit to Battery GEM REFER to Section 413-01 . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure GEM REFER to the Symptom Chart. P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground GEM GO to Pinpoint Test C . P1820 Transmission Transfer Case Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test B . P1822 Transmission Transfer Case Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test B . P1824 Transmission 4-Wheel Drive Clutch Relay Circuit Failure GEM GO to Pinpoint Test A . P1826 Transmission 4-Wheel Drive Low Clutch Relay Circuit to Battery GEM GO to Pinpoint Test A . P1828 Transmission Transfer Case Counter Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test B . P1830 Transmission Transfer Case Counter Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test B . P1836 Transmission Transfer Case Front Shaft Speed Sensor Circuit Failure GEM GO to Pinpoint Test A . P1837 Transmission Transfer Case Rear Shaft Speed Sensor Circuit Failure GEM GO to Pinpoint Test A . P1838 Transmission Transfer Case Shift Motor Circuit Failure GEM REFER to the Symptom Chart. P1846 Transmission Transfer Case Contact Plate 'A' Circuit Failure GEM REFER to the Symptom Chart. P1850 Transmission Transfer Case Contact Plate 'B' Circuit Failure GEM REFER to the Symptom Chart. P1854 Transmission Transfer Case Contact Plate 'C' Circuit Failure GEM REFER to the Symptom Chart. P1858 Transmission Transfer Case Contact Plate 'D' Circuit Failure GEM REFER to the Symptom Chart. P1866 Transmission Transfer Case System Concern - Servicing Required GEM REFER to the Symptom Chart. P1867 Transmission Transfer Case Contact Plate General Circuit Failure GEM REFER to the Symptom Chart. P1874 Transmission Automatic Hall Effect Sensor Power Circuit Failure GEM GO to Pinpoint Test A . P1875 Transmission Automatic Hall Effect Sensor Power Circuit Short to Battery GEM REFER to the Symptom Chart. P1891 Transmission Transfer Case Contact Plate Ground Return Open Circuit GEM REFER to the Symptom Chart. P1892 Trans. Automatic 4-Wheel Drive 4X4 Mechanical Lock Output Circuit Failure GEM GO to Pinpoint Test B . P1893 Trans. Auto. 4-Wheel Drive 4X4 Mechanical Lock Output Short to Battery GEM GO to Pinpoint Test B .
• Your best bet , take it to a qualified repair shop .

unfortunately what it sounds like is the transfer case like you suspect. inside are bearings and gears and a chain what happens is the chain will stretch and cause this problem it will actually jump the teeth on the gears, you will need to have the chain replaced in the transfer case. sorry to have to tell you this but i hope it helps.

Yes it can, just place your Transfer Case in Neutral position.
Shifting into NEUTRAL
To shift the transfer case to NEUTRAL do the following:

Make sure the vehicle is parked so that it will not roll.
Set the parking brake.
Start the vehicle or turn the ignition to RUN.
Connect the vehicle to the towing vehicle.
Put the transmission in NEUTRAL (N).
Shift the transfer case to 2HI.
Simultaneously press and hold the 2HI and 4LO buttons for 10 seconds. The red NEUTRAL light will come on when the transfer case shift to NEUTRAL is complete.
Shift the transmission to REVERSE (R) for one second, then shift the transmission to DRIVE (D) for one second, or FIRST (1) for vehicles equipped with a manual transmission.
Turn the ignition to LOCK.
Place the transmission shift lever in PARK (P), or FIRST (1) for vehicles with a manual transmission.
Release the parking brake prior to towing.
Shifting Out of NEUTRAL
To shift out of NEUTRAL:

Set the parking brake and apply the regular brake pedal.
Shift the transmission to NEUTRAL (N) and turn the ignition to RUN with the engine off.
Press the button for the desired transfer case shift position (2HI, 4HI, AUTO 4WD or 4LO).
After the transfer case has shifted out of NEUTRAL the red light will go out.
Release the parking brake.
You may start the engine and shift the transmission to the desired position.
Excessively shifting the transfer case into or out of the different modes may cause the transfer case to enter the shift protection mode. This will protect the transfer case from possible damage and will only allow the transfer case to respond to one shift per 10 seconds. The transfer case may stay in this mode for up to three minutes.
NEUTRAL: Shift the vehicle's transfer case to NEUTRAL only when towing your vehicle.
Good luck and hope this answers your question.

ok.. Start with unhooking the battery, removing both drivelines, exhaust, and crossmember while supporting transmission with a jack. Remove all wiring connectors and hoses from transfer case. Remove starter, and torque converter bolts thru the starter hole..
remove the six transfer case to adapter bolts and slide off the transfer case. Disconnect all electrical connectors, hoses, and unbolt transmission cooler lines. Support the transmission with a jack, and remove all of the bellhousing bolts. You should be able to wiggle the transmission, and get it to back off of the engine and then should be able to lower it. Reverse procedure to install, and make sure the new one has fluid in it before you start it up.

THE TAILSHAFT OF A 4x4 TRANS WILL HAVE A LARGE FLANGE THAT A TRANSFER CASE ATTACHES TO.

I am going to guess that you're correct on your Transmission, is it only when your vehicle is getting ready to shift?