4wd not engaging front wheels

535

Asked by markmaki Jul 27, 2007 at 02:57 PM about the 2002 Chevrolet Tracker LT 4-Door 4WD

Question type: Maintenance & Repair

The front wheels will not engage and the light will not come on the dash when I shift into 4wd.  What is the usual problem?

20 Answers

27,625

Hi markmaki, If your Tracker shifts into 4wd electronically, you may have a blown fuse or bad switch. If it's shifted into 4wd by a shift lever your linkage may have come apart. Either mechanism could fail shifting into 4wd if the front differential is not working properly. You could have low lubricant levels or a stripped gear thus not allowing the differential to engage. Good luck!

27 people found this helpful.
535

Actualy this answer is all wrong, but thanks any way. I found the problem is a small air compressor mounted behind the license plate which is broken and not running right. It is called the actuator pump and it blows air into the front drive shaft to lock the wheels into the gears. It is a very small part and costs $325 from the dealer and installs in minutes.

45 people found this helpful.
250

The front diff is also a known issue. There are a series if diaphrams that hold the pressure from the air pump. This can be tested by disconnecting the pump and using a compressor in its place. If the pressure holds, the diff is ok. If it fluctuated, the diaphram is shot. Because of it being a known problem, you can get dealer rebuilds (12 months/12,000 mile warranty) for about the same price as rebuilding the existing diff. I went through all this last spring. I had to replace the pump and diff on my 99 Tracker

25 people found this helpful.
225

Even though the front hub are auto-locking,,, it takes a partial to full rotation of the tires them selves to be able to enage the drive system from the transfer case/or transmission.

12 people found this helpful.
2,055

Its usually the actuator. I will rebuild your actuator or sell you a rebuilt one 1/4 the price of new. But first lets determine if its the problem. troyobe88@gmail.com

48 people found this helpful.
260

I have the same issue. 4WD light flashes, front wheels engage but disengage almost immediately. HERE'S THE KICKER, 4WD works in reverse?!? but the light still flashes. WTH?

26 people found this helpful.
2,055

Sounds like your Actuator Pump is bad, that is generally easy to determine from the light blinking. It is likely the actuator will fix your problem. Going in reverse may take slight pressure off the slider within the differential and allow the failing pump to develop slightly more pressure to grab 4WD temporarily. Also now the rear wheels are pulling. At is core your pump can't develop enough pressure to move the diaphragm slider within the diff. Contact me directly via Troyobe88@gmail.com if you want me to test and/or rebuild it for you. Also, for ALL READERS, make sure your tires are all the same regarding wear. That can cause engage and disengage issues but not likely the issue here. .

19 people found this helpful.
2,055

If you need additional and extensive guidance on testing the Actuator Air Pump, Actuator, pictures, refurbished and new pumps, please visit my website ActuatorPumpRepair.Com. Also, please keep CarGurus in mind for future car questions

24 people found this helpful.
2,055

I want to add clarity to my earlier answers as I used the word Actuator in a place where I intended to say Actuator Pump. The ACTUATOR PUMP (outside the diff and easy to replace), also known as Actuator Air Pump, Air Pump or compressor, is a small air pump that puts 5,4 to 8.25 LBS of pressure into the Actuator. The Air Pump is a pressure pump despite it sometimes being called a vacuum pump. The ACTUATOR (within the front differential) is equivalent to a balloon. When air is pumped in it expands and engages the gear within the differential. The actuator either holds air or is doesn't just like a balloon. So engagement issues are usually the pump, disengagement issues are usually the pump, blinking light is always the pump, if a pump runs for 10 seconds and then shuts off it is the pump as it should run 3 seconds then shut off and stay off and the 4 wd light indicator should be on. A blinking light means the pump keeps coming back on and reengaging the 4wd. The actuator wasn't made to keep expanding and contracting and the differential doesn't like it either, you will develop other problems. On the website I have pumps, Differential bearing & seal Kits and other support information for testing the pump, actuator and electrical.

39 people found this helpful.
90

If its not the pump what should be checked next

9 people found this helpful.
2,055

ActuatorPumpRepair.com has the additional test info as well as New or Refurbished parts 4WD and Differential Parts. Then please share your findings on CarGurus

8 people found this helpful.
295

Please Help. Anything at all would be helpful. I'm having the same problems with my 4x4 on my 89 Chevrolet Tracker, except My light on the dash of my tracker lights up perfect and dont blink or anything else. It stays lit all the time, but when it's in 4wheel only the back wheels will spin. The front will not engage. Every now and then it will engage, but stops almost instantly. It's a lever 4x4 H/L/N, not a push button with auto hubs, not locking hubs that you have to turn on the front wheels. Someone told me it's the actuator to engage the front 4x4, but I can't locate it. Can anyone tell me, send a pic or video, or something to locate it? Is there a way to test it? Is there a way to bypass it and lock it into 4wheel either all the time or only when I need it, without having to replace the actuator? If it's not the actuator, what else could it possibly be? It's on a 1989 Chevrolet Tracker 4x4 1.6L 4cyl 4door. Please can anyone help me. Email me @ johnpierce61@gmail.com Thank you in advance.

20 people found this helpful.
50

if your 4 wheel light stays on steady without flashing the problem is in the hubs. Mine was doing the same thing. After tapping them with a hammer they worked just fine. I just took mine off and apart and greesed everything real good. They've been working just fine ever since

5 people found this helpful.
10

I have a 2000 tracker and the 4x4 light flashes but dose not engage where should I start

1 people found this helpful.
2,055

Air pump mounted on engine side of front bumper. Find the rubber hose coming off the nipple closest to the engine. Crimp that pressure hose to fully restrict all air pressure going to the differential. Key on, put into 4wd, if the light stays solid then your problem is down stream leak in the line or in the actuator within the differential. If the 4WD light is still blinking then the pump is shot. We sell new or refurbished on the website ActuatorPumpRepair.com, we also have additional testing info. WE NOW CARRY TRANFER CASE PARTS

12 people found this helpful.
2,055

4WD Hi / Lo switches located on the Transfer case. You remove the covers and go through the shift / E-Brake area to replace these, we sell them on the website ActuatorPumpRepair.com.

7 people found this helpful.
20

Just started having this problem with my 99’ two door, the dash 4x4 doesn’t light up and the wheels don’t spin. HELP! Anybody know the problem?!

2 people found this helpful.
2,055

It is most likely the pump. About 4 posts up ( Rusty Pic) I discuss how you can test the pump to be sure. The test is simple and by far the best place to begin. For more testing info and to get a replacement pump go to out website ActuatorPumpRepair.com.

6 people found this helpful.

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