front axles always engaged??

[bikenutty]

rotated my tires and happened to notice my axles would not remain stationary while turning the rotor, I tried holding the axles still and they felt mechanically connected to the hubs. I don't recall my FX4 doing this.

Aren't they vacuum actuated??

$$

 

[Dane]

Yes. Vacuum DISENGAGES 4WD - very important detail. Your truck FAILS into 4WD with not vacuum, no 2WD as you might expect (another way is to say that vacuum engages 2WD, not 4WD). So, unless your vacuum is holding with the truck turned off (it should, at least for some time), it would be in 4WD. Try it with the motor running. If you are in two wheel drive, motor running, and your front wheels are engaged to your axle, you have a problem with your IWEs or the vacuum system. Very common issue.

 

[zombiekiller]

Yes. Vacuum DISENGAGES 4WD - very important detail. Your truck FAILS into 4WD with not vacuum, no 2WD as you might expect (another way is to say that vacuum engages 2WD, not 4WD). So, unless your vacuum is holding with the truck turned off (it should, at least for some time), it would be in 4WD. Try it with the motor running. If you are in two wheel drive, motor running, and your front wheels are engaged to your axle, you have a problem with your IWEs or the vacuum system. Very common issue.

that is incorrect for gen2s.

If there is no vacuum, the IWEs do lock and the front axleshafts will spin.

the truck is NOT in 4wd at this point. The transfer case is not full time, therefore without shifting the tcase into 4A, 4L or 4H in order to send power to the front driveshaft, you are not in 4wd.

 

[zombiekiller]

rotated my tires and happened to notice my axles would not remain stationary while turning the rotor, I tried holding the axles still and they felt mechanically connected to the hubs. I don't recall my FX4 doing this.

Aren't they vacuum actuated??

$$

yes, they are, but lack of vacuum engages the IWE, which connects the hub to the axle shaft.

trucks don't hold vacuum when turned off, so when the truck is off, the iwes connect. If you turn the truck on and try the same thing, unless you have a problem, it will spin free.

 

[Dane]

that is incorrect for gen2s.

If there is no vacuum, the IWEs do lock and the front axleshafts will spin.

the truck is NOT in 4wd at this point. The transfer case is not full time, therefore without shifting the tcase into 4A, 4L or 4H in order to send power to the front driveshaft, you are not in 4wd.

Well ok, yeah. The transfer case obviously isn't engaged. Same with Gen 1s. Kinda splitting hairs given what he's asking about though.

 

[tltoronto]

On flat ground, (empty parking lot) put yout truck into neutral while idling, crank the wheel all the way to the left/right, hop out, and go to either front wheel (whichever is pointing out, give the truck a push against the tire rolling the truck a bit. You will clearly see wether the CV is spinning or not. when done, crank the wheel to the other side, check other CV. On my truck, the vaccum pressure hangs around for about 20 minutes when the truck is off. It is completely normal for the CV to be engaged after a while of the truck being turned off. (JAcking truck up, removing wheels, having beer, wiping shocks and then seeing CV's spinning.) Not a stress!

 

[bikenutty]

good information all, thanks. I assumed vacuum engaged the axles. Still don't remember my FX4 being that way though... I'll ensure they disengage correctly when running.