So my sweetie and I are driving on the freeway when it starts snowing.  Traffic slowed to about 45 mph, and when we were obviously driving on snow, I slipped it into 4Hi.  Immediately heard a noise that I can best describe as a large blower fan with a big dry leaf stuck in it.  It changed with the speed of the car, and after 20 or 30 minutes, slowly went away.

Next time I used 4wd it was just to get out of the driveway.  Same noise.  As soon as I hit the pavement I put it into 2Hi but the noise didn't stop!  I stopped at a red light, and there was no noise when the light turned green.

Yesterday I used 4Hi to get out of the driveway again, hit 2Hi when I got onto the pavement, then stopped the car thinking the noise would stop also.  It didn't!  Not until I drove down the street and pulled into someone's driveway in order to turn around.  No noise after that.

Anybody care to guess exactly what is getting ready to break?  My main concern is whether I'm simply going to lose my four wheel drive, or if something is going to grenade and leave me stranded somewhere, possibly with a Hazmat team pointing and mumbling.

Can we safely assume you're driving an unmodified '00 Tracker?

Next time it happens, when you shift back to 2H, stop and backup a few feet, and then go forward again - does the noise stop?

I'm wondering if you're having a problem with drive-train wind up, preventing it from coming out of 4H.

Can we safely assume you're driving an unmodified '00 Tracker?

Next time it happens, when you shift back to 2H, stop and backup a few feet, and then go forward again - does the noise stop?

I'm wondering if you're having a problem with drive-train wind up, preventing it from coming out of 4H.

I was wondering the same thing, Fordem, but the piece that throws me is he said it immediately started the noise when he placed it into 4WD. 

I'm wondering if the dog gears in the front diff (IF he has a 2nd gen truck) are not meshing fully and simply over riding each other making that burring sound.  I can see the dog gears not releasing AFTER you have had it in 4WD from drive train bind, but if the air actuator is working properly, he shouldn't be hearing any prolonged burring noise UNLESS he has manual hubs and if so, they may be frozen up and not fully engaging the ends of axle spline/s.

My WARN hubs do this typically at the start of winter IF I haven't had the front hubs locked in for a while.  Of course my front axle doesn't pull either until I've tapped on the hubs a couple times to free up the action.

It's a 2000 2-door with automatic, stock as a stove except for fancy wheels.  I don't yet know enough about this rig to troubleshoot such problems.

If my front diff gears weren't meshing, then I wouldn't have 4wd, would I?  I'm certain that when I shift into 4Hi, power goes to the front wheels.  (This is simply based upon how it gets out of the foot of snow in the driveway.)  And yup, I hear the noise the very moment I slip it into 4wd.  I know what axle wrap feels like in a steering wheel and I've not experienced that in this Tracker.

Yesterday I took it out again.  4Hi to get out of the driveway, and in and out of 4Hi for about half a mile, "in" when I was on snow and "out" when I was on pavement.  I was "out" for a couple hundred yards before stopping to make a left turn.  AFTER stopping, there was no noise, but up to that point the noise was constant both in and out of 4wd.

My wife drove this rig through four winters before it was recently handed down to me.  I always told her that she shouldn't be in 4wd unless the road was slippery, and if in doubt as to road conditions (is it water or ice?) to use 4wd since I could replace the Tracker much easier than I could replace her.  So it's possible that it was driven on wet pavement in 4wd in the past.  Knowing my wife, maybe even some dry pavement.

Is it possible that I'm dealing with two separate issues?  One being simply bad u-joints on the transfer case drive line, and the other being a reluctance to disengage 4wd until I've come to a stop?  I've FELT bad u-joints on other vehicles but have never HEARD them before.

(I must research these manual hubs you mentioned.  Simple is good.)

I know what axle wrap feels like in a steering wheel and I've not experienced that in this Tracker.

Axle wrap?  Where did that come from??  I don't think Norm or I even suggested it might be a problem - it's kind of hard to get axle wrap on a coil sprung truck.

Is it possible that I'm dealing with two separate issues?  One being simply bad u-joints on the transfer case drive line, and the other being a reluctance to disengage 4wd until I've come to a stop?  I've FELT bad u-joints on other vehicles but have never HEARD them before.

First - not wanting to "disengage" 4WD was the thought behind my previous response - not as the cause of the noise, but because the noise continues after you go back to 2WD.  I have personal experience, both feeling & hearing defective UJs, and I feel that is unlikely - it's usually more of a vibration than a noise - and if it were the UJs, it would/should either be continuous - if the rear UJs - or stop when you shift back to 2H - because the front UJs stop rotating at that point, or at least should stop unless there are faults in two other places - the transfer case and/or the front differential dog clutches.

The way the 4WD system on that vehicle works, it's fairly "positive" - you push the lever forward and it slides a hub in the transfer case into mesh, you pull it back and it pulls the hub back out, disconnecting the feed to the front axle - at the same time, the shift shaft will close (or open) a switch that triggers the engagement of the front freewheel mechanism in the axle.

Can you check the 4WD light - it should come on with a few seconds of your selecting 4H and go out within a few seconds of your going back to 2H - does yours work correctly?

My mistake--what you call drive train windup, I've always called (erroneously, I know) axle wrap.  I never owned a vehicle powerful enough to produce true axle wrap!

Yes, the indicator light goes on and off just like it should.  The entire 4wd system seems to work properly, making the little rig very surefooted in the snow.

Here's a new wrinkle.  I put it in 4Hi for about 30 feet to back out of deep snow.  Without stopping and still in reverse, I slipped it into 2Hi and backed onto the street.  I was at low speed, of course, but heard no noise in reverse, and no noise once I hit the pavement and drove away.  The noise seems to be a "goin'-forward" problem.

Could there be some resistance in the front differential to disengaging?  Is the switch internal or externally mounted?  You don't happen to have a link to an exploded drawing, do you?

I swapped computers recently and don't currenlty have access to my pic library, but rhino man has a link for Suzuki.  Open up the service manual files s for the Grand Vitara (GV) and it should be almost identical.

http://www.rhinoman.org

If you still have this noise, have you checked your CV's and axle shafts?  A torn CV boot could (?) make noise while turning in one direction only, or something wrapped up on one of the front axle shafts, and auto hubs do not always disengage immediately when the diff disengages.  A bad CV joint should produce more vibration than noise, but its a possibility also.  So check both front axle shafts for torn boots or being able to physically move, not turn, them with your hand.