I shifted into 4HI and 4LO yesterday for the first time in about 3 weeks. when i first shifted it the light came on but when ever i give it gas it usually cuts out. it even cut out and back in snapping the front wheels into motion and out again. when cruising at a constant speed it sometimes stays on but when it's actually needed it cuts out. possibly the air powered mechanism that engages it??? also my transfer case has a leak at the rear drive shaft, i think i need a new seal there. would that have anything to do with 4x4 not working? thanks!

Cuts out as in engine stalls?

A leaking rear output shaft seal will not affect the way the 4WD freewheel mechanism (engages/disengages the front freewheel clutch & turns the light on/off) works.

no sorry i should have specified that when i say cut out i mean the 4WD light turns off and power is only from rear wheels.

The 4WD light going on & off and the freewheel clutch engaging & disengaging will either be an air leak in the system or possibly a broken wire/bad connection.

The set up is triggered by a switch on the transfer case that grounds a wire leading to the 4WD controller, which can either be a separate module (up under the dash near the accelerator pedal), or integrated into the ECU (under the glovebox) - the 4WD controller then switches an air pump module (behind the front bumper) on & off as required, and the air flows through a hose to the front differential.

What I would do in your case is find the air pump connector and wire a 12V test lamp between the red & black wires (leaving the pump connected), position the lamp where I could see it from the driver's seat and then make another test - if the test lamp stays on the problem is going to be in the air side of the system, if the test lamp blinks out, the problem will be on the control side.

One important point - if the 4WD controller does not see feedback from the pump - it will shut the system down after 10 seconds, so if your test light only stays on for 10 seconds at a time, that's the reason.

thanks i will give that try later. i can hear the pump going on, then it will kick in again when the light turns off. I'm thinking it might be air related because the light will only be lite in light pressure situations. I'll get someone to swtich it back and forth while i'm under it today with some dishsoap on the lines or something to help find it???

Under normal circumstances the 4WD controller will supply power to the pump as long as 4WD is selected, the pump turns on & off to maintain pressure through an internal sensor and the same sensor controls the 4WD light, so if the pump is running the light goes off, and when the pump is off the light goes on.

It's a little unusual for the on/off to coincide with "4WD load" so my suspicion is that something in the drive line may be moving - either the transfer case or the front axle - under load, and the movement causes the problem - maybe a cracked hose between the pump and the axle housing so the movement cause the crack to open up.

Thanks for the info i'm going to remove the hose, inspect for damage and replace it if needed. then if that doesn't work i'll be back wondering what to do haha

took me a while but i'm back, i plugged in the pump into it's socket with nothing on the air output and it ran continuously. with the pump output plugged 4wd light takes a while to turn on about 5 seconds. stays lit for about 10-15 seconds and turns off again for a couple seconds. One really weird thing is the pump just 'chrips' like a half second, normal or no? i checked the hoses they all look pretty good. one thing i noticed is a leak on the passenger side axle right next to the diff, could air be leaking out here maybe?? what a headaacheee wish it was just fully manual 4x4

If the pump is connected electrically but has no connection on the outlet, when you select 4WD it should run for 10 seconds and stop without the 4WD light turning on - there is a protective circuit in the controller that will shut it off.

What you need to do now is disconnect the hose from the outlet and plug the outlet and then select 4WD and see what happens - the pump should run for a few seconds and stop, and the 4WD light should come on and stay on

If you cannot get the two things above to happen, the pump has a problem - if when the outlet is plugged the pump starts & stops and the 4WD light flashes, there is probably an internal air leak in the pump - typically this is repairable.

If the two things do happen but when the pump is connected to the diff it starts & stops the air leak is most likely in the diff actuator and that's a pain in the backside repair - the diff has to come out.

Some folks have tackwelded the clutch assembly in the diff and fitted free wheeling hubs rather than replace a leaking actuator.

like i said eailer, with the outlet plugged the pump chirps a few few times, takes about 6-7 seconds for the 4wd to come on. once it's on it will turn off for about 1-2 seconds about 5 times in the span of a minute. so it looks like it may be the pump.

Ahh - I see - you have an air leak in the pump module then - the problem will most likely be rust on the nose of the "dump valve".

New modules are available from the dealer, kind of pricey though, used modules can be had from the various used Suzuki part vendors, or you can try your hand at a fix - here's a pictorial "tear down" - if the pictures don't show for you, right click the image and select open in a new tab.

i think this is the perfect excuse for me to ditch the air and switch to a true part time system, i have some manual hubs now anyway so the work is half done, well more like an 1/8th done haha, thanks for all the help!