4wd keeps disengaging

[hurleyman07]

hey guys i have s 2004 ford ranger when you put it in 4wd high or low and get it under a load or turn the wheel a little at about 3000rpm it disengages the 4wd and makes a loud popping noise ive put 2 different transfer cases in it new hubs new cv axles the only thing i havent replaced is the front axle do you think it could be internal in the front gearing?

 

[RonD]

Welcome to TRS

2004 has Live Axles up front so those can't "disengage"

I can't see the front differential being the issue if it "worked again" with 2nd transfer case, these don't tend to self heal, lol
It is an OPEN differential so if either axle shaft becomes easier to turn, disengages, then you do loose 4WD

Was the first transfer case broken?
was it disassembled to see if or what broken inside?

The 4x4CM, control module, is a known failure point on 2001-2011 Ranger 4x4s
Its possible it is moving transfer case shift rod via shift motor when you are bouncing around off-road
You could try shifting into 4WD then unplugging the shift motor's 8 wire connector, disabling 4x4CM control, and hitting the trails

4x4CM is located behind the radio in 2004-2011 Rangers

 

[wildbill23c]

The front end is independent suspension and I believe they use CV axles, if one of the CV axle shafts has popped out of the differential you'll certainly not have 4WD, or if you have a CV joint that has failed and you are turning and it separates itself you'll lose 4WD...if you are just changing transfer cases you obviously aren't correcting the problem. I doubt its the shift motor as its engaging. My thoughts would be an axle popping out of place. You'll have to put the front end up on stands and pull the front wheels most likely for easier access to see if those front shafts are pulling out of the differential.