Hello, the snapping noise is usually a sign, that a front axle universal joint is worn. These will need to be inspected and replaced.
As far as the 4wd drive not engaging, you may have linkage to the transfercase binding, a broken joint at the axle or propeller shaft or internal transfer case damage. The fluid should be changed every 30,000 mi. By the way, I have also seen in some cases that mismatched tires, and tread depth cause 4wd engagement and disengagement problems.
DIAGNOSIS AND TESTING - TRANSFER CASE
Before beginning repair on a suspected transfer case malfunction, check all other driveline components beforehand.
The actual cause of a problem may be related to such items as: front hubs, axles, propeller shafts, wheels and tires, transmission, or clutch instead. If all other driveline components are in good condition and operating properly, refer to the Diagnosis Chart for further information.
|Condition ||Possible Cause ||Correction |
|Transfer Case difficult to shift or will not shift into desired range. ||1) Vehicle speed too great to permit shifting. ||1) Stop vehicle and shift into desired range. Or, reduce speed to below 3-4 km/h (2-3 mph) before attempting the shift. |
|2) If vehicle was operated for an extended period in 4H on a dry paved surface, the driveline torque load may be causing a bind. ||2) Stop vehicle and shift the transmission into neutral. Shift the transfer case to 2H and operate vehicle in 2H on dry paved surfaces. |
|3) Transfer case external shift linkage binding. ||3) Lubricate, repair, or replace linkage bushings, or tighten loose components as necessary. |
|4) Insufficient or incorrect lubricant. ||4) Drain and refill to edge of fill hole with Mopar® ATF +4, type 9602, Automatic Transmission fluid. |
|5) Internal components binding, worn, or damaged. ||5) Disassemble the transfer case and replace worn or damaged components as necessary. |
|Transfer Case noisy in all operating ranges. ||1) Insufficient or incorrect lubricant. ||1) Drain and refill to edge of fill hole with Mopar® ATF +4, type 9602, Automatic Transmission fluid. |
|Noisy in, or jumps out of, four wheel drive low range. ||1) Transfer case not completely engaged in 4L position. ||1) With the transmission in NEUTRAL, or the clutch depressed in the case of a manual transmission and the vehicle moving under 3-4 km/h (2-3 mph), shift the transfer case to NEUTRAL and then shift into the 4L position. |
|2) Shift linkage out of adjustment. ||2) Adjust linkage. |
|3) Shift linkage loose or binding. ||3) Tighten, lubricate, or repair linkage as necessary. |
|4) Range fork damaged, inserts worn, or fork is binding on the shift rail. ||4) Disassemble unit and repair as necessary. |
|5) Low range gear worn or damaged. ||5) Disassemble unit and repair as necessary. |
|Lubricant leaking from output shaft seal or vent. ||1) Transfer case overfilled. ||1) Drain lubricant to the correct level. |
|2) Vent closed or restricted. ||2) Clear or replace vent as necessary. |
|3) Output shaft seals damaged or installed incorrectly. ||3) Replace seal as necessary. Check to ensure that another component, the propeller shaft slip yoke for example, is not causing damage to seal. |
|Abnormal tire wear. ||1) Extended operation on hard, dry surfaces in the 4H position. ||1) Operate vehicle in the 2H position on hard, dry surfaces. |
I hope this helped if so an accept is appreciated