Transfer case jumps out of gear

On the transfer case
Transfer Case - Electronic Shift
The four-wheel drive electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4WD HIGH, and 4WD LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators: one for 4WD HIGH which appears as 4WD, and one for 4WD LOW, which appears as 4WD LOW. Shifts into 4WD HIGH can be made at any speed. When shifting into 4WD HIGH with the vehicle stationary, tooth blockage may occur preventing shift completion. When the vehicle is driven above 8 km/h (5 mph) the shift will complete. When shifting in or out of 4WD LOW, the four-wheel drive (4WD) control module requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission be in NEUTRAL (automatic transmission) or the clutch pedal be depressed (manual transmission).
The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4WD HIGH, 4WD LOW, and 2WD range positions.
The four-wheel drive (4WD) control module controls the gearmotor encoder assembly that shifts between 4WD HIGH, 4WD LOW, and 2WD modes.

I guess you probably don't know what transfer case you have ?
SERVICE 4WD
Refer to
?€¢
Transfer Case Description and Operation in Transfer Case - NVG 149-NP3

?€¢
Transfer Case Description and Operation in Transfer Case - NVG 246-NP8

?€¢
Transfer Case Description and Operation in Transfer Case - NVG 261-NP2

?€¢
Transfer Case Description and Operation in Transfer Case - NVG 263-NP1

The NVG 246 EAU provides 5 modes, Auto 4WD, 4HI, 4LO, 2HI and Neutral.
The four manual mode, or range gear positions, of the NVG 261 transfer case are:
?€¢
2HI - 2 wheel drive high range

?€¢
4HI - 4 wheel drive high range, part-time

?€¢
4LO - 4 wheel drive low range, 2.72:1 gear ratio reduction

?€¢
N - Neutral, 4 wheel

The NVG 263 transfer case provides the driver with 4 manual mode/gear positions:
?€¢
2HI - 2 Wheel Drive high range

?€¢
4HI - 4 Wheel Drive high range

?€¢
4LO - 4 Wheel Drive low range

?€¢
Neutral

With the info I've given you ,you should be able too now !
There is probably a code stored somewhere !
DTC B0790 DTC B2725 DTC C0300 DTC C0305 DTC C0306 DTC C0321 DTC C0327 DTC C0359 DTC C0374 DTC C0379 DTC C0550.

the chain is situated at the rear of the box and connects the output shaft of the gear box to the input shaft of the transfer case . it does wear and get loose and the gear teeth wear as well. all that is required is a chain and 2 gears and labour to replace
i feel that replacing the transfer case will not achieve much so i suggest that you talk with a service dealer to get a better idea of what is involved.

Do you have mechanical-shift four wheel drive,or electronic-shift, 4WD system ? Any lights lit on the dash ?
The electronic-shift, 4WD system consists of the following components:

• Transfer case (For transfer case repair procedures, refer to Section 308-07B ).
• 4WD control module (For 4WD control module installation, refer to 4WD control module in this section.)
• Mode select switch (MSS)
• Gearmotor encoder assembly
• Automatic locking hubs (hub locks)
• Pulse vacuum hub lock (PVH) solenoid and vacuum lines
• The mechanical-shift four wheel drive (4WD) system consists of the following components:
• Transfer case (For transfer case repair procedures, refer to Section 308-07B ).
• Transfer case shift lever
• Manual locking hubs
• 4x4 indicators
• Shift linkage (hub locks)

1. • 1 Start your Dodge truck's engine.
     
   • 2 Turn the electronic transfer case from "2WD" to "4WD Lock" to engage the high range 4WD, if the dodge truck is equipped with an electronic transfer case; otherwise, shift the transfer case lever from "2H" to "4H." The electronic transfer case is located on the instrument panel and is marked with "2WD," "4WD Lock" and 4WD Low." The lever-equipped transfer case is located to the right of your leg and is marked with "2H," "4H" and "4L."
     
   • 3 Shift the transmission into "Neutral" while the vehicle is either stopped or rolling at 2 to 3 mph to begin engaging in the low range 4WD. Turn the electronic transfer case to "4WD Low," if the Dodge truck is equipped with an electronic transfer case; otherwise, shift the transfer case lever from "2H" or "4H" to "4L."
     
   Tips & Warnings
   • Indicator lights will come on and alert you that your vehicle is in either the high or low range of 4WD.
     
   • Do not engage in the low range of 4WD drive if the transmission is in gear; you must shift to "Neutral" first.
     
   • Many Dodge trucks allow you to shift from 2-wheel drive to the high range of 4WD at up to 55 mph--consult your truck's manual to ensure that this is possible. Do not exceed 55 mph while engaged in the high range of 4WD. Do not exceed 25 mph while engaged in the low range of 4WD.
     
   • Do not engage in 4WD unless you are on slipper or rocky roads.
     

make sure your 4WD switch is working.and fuse is okay.because your 4WD is control by 4 electric shift motors in which drive a rotary cam which moves the mode fork and range fork inside the transfer case to select between 2WD HIGH A4WD - 4WD HIGH AND 4WD LOW RANGE.a shift motor sensing plate on the shift motor monitors the range in which the transfer case is operating a transmission range sensor monitors the gear position of the transmission.which must be in neutral to shift into low.a pair of solenoids one for 2WD one for 4WD.mounted on the upper right firewall route vacuum to the vacuum motor which engages and disengages the center axle disconnect collar in the front axle assembly.a 4 x 4 shift motor relay module contains two GEM controlled relays which shift the transfer case shift motor between 2WD and 4WD modes.a solid state clutch relay activates the A4WDclutch inside the transfer case.

...I agree with the last poster. My truck had a pinion seal leak and let all of the lube out and it whined just like you say yours did.

you should have 2 hi 4 low 4 hi and nuetral on your transfer case 4 hi would be anything up to 35-40mph or lower 4 low is almost never used it just gears down your t case if your climbing a hill or super stuck the manual locing hubs are extremely reliable do not have them locked on dry pavement or concrete just loose dirt snow ice ect put the tranny gear shifter in nuetral to put your t case in 4 low

try putting in nuetral and then shift into high gear . if still does not work sounds like the 4x4 acctuator is bad

check the rear differential as well as the transfer case...you may have broken something in both of them...i have seen it happen...since 4low uses a different gear it is possible for it to move in low and not 4 high