tankwilson

Ok...just bought a pretty decent little 99 chevy tracker. I have done some reading but haven't come up and answer to my question (title of my post). My 4wd dash light blinks off and on constantly when 4x4 is engaged... I have read it could be the air pump or a vacuum leak somewhere.


Question.... Could I just install manual lock out hubs and plug the vacuum line coming from the diff to the air pump and still have everything work fine? I assume my 4wd light wont work but don't care? Has anyone done this as a fix?

MySelf

(My answer is based on what I know regarding my 2001 Tracker.)

My understanding is that the pump creates pressure, not vacuum, which seems correct. There is a bladder which has to inflate in order for the gears to engage. There is a spring pressing on a plate attached to the bladder which keeps it flat when it is not inflated.

When the bladder inside the differential housing (the carrier) fills it engages the axle shaft on the passenger side with the rest of the differential gears.

Because of the design, if you truly wanted to switch to manual hubs and not use the pressure bladder, you would need to replace the differential with a full-time one or defeat the design of the current one - which is disconnected by default.

I have two tracker differentials out of the carrier - one intact, one disassembled - I can upload pics, if you want.

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My light flashes as well. I assume I need to evaluate the pump and replace the external hoses, and add clamps. There should only be one or two hoses which need to be addressed. One from the pump to the delivery pipe (if there is one) and one from the pipe to the carrier - this one exists.

ninja3

the issue is probably the 4 wheel drive pump as stated above. once the pump loses enough pressure it will restart till it gets to around 5 lbs and shut off again. as this happens your light will blink. you are probably in 4 wheel as long as your pump can keep up. i believe it was when you get down to 2 to 3 lbs it will restart. if the light was not coming on the pump has probably totally failed and seized. i read on my other suzuki site how to take the pump apart and reseal it. it worked great on my 2003 and has held up the past 2 years with no more blinking light. the only place to get a new one is at dealer and they are 500 bucks for it. you can find it behind the front bumper on pas side. it is mounted in a bracket held by 2 bolts to bumper. it can be reached without bumper removal. one hose coming from engine compartment that sucks the air in and the other runs to front dif. just be careful taking hoses off at pump cause they connect to plastic so no pliers here. just pull them off. you say you don't care if 4 wheel works but this is helpful to others with same issue that want to fix it without having to spend 500 on a new pump if repairable.