So I take the sidekick out to play today and start spinning out on a hill I know I should be able to climb with ease in 4wheel low.  My buddy hopped out and confirmed that the front wheels were not turning. 
     Went home and jacked up all 4 wheels.  When I put it in 4WD, the front driveshaft does engage and turn but that's where the buck stops.  Now I don't know much about 4WD and how it works but common sense tells me the front diff is dropping the ball. 
    When I get under the trucklet and manually spin the drive shaft with my hand in 2WD, the right front axle turns but not the left.  When I turn the front wheels by hand the axles do not turn on either side. 
    What more do I need to do to definately say its its the front diff that's ruining the party?  Or can we conclude that already?

Thanks

Jon

As you may already know these vehicles have "open" Differentials. What this means is that if you jack the vehicle up and spin the front right tire one way the left will go the opposite. The cause for this is the spider gears turning inside the differential on one side causing the opposite reaction on the other. If your Zuk has auto hubs on it it may be a hub not engaging. I would troubleshoot it by checking by spinning one wheel by hand jacked up and seeing if the other spins opposite. if it does then your gearing should be ok. if not it could be a gear issue. A friend had a similar problem and it was a hub related issue. Good luck hope this helps. Youtube has some good videos on how 4wd works or look it up on here.

Thanks for the reply.  When I had the truck in 4WD, jacked up, I could still turn the wheels freely but could not turn the driveshaft.  It is as if putting it in 4 WD changed nothing beyond the drive shaft.

  When I turn the front wheels by hand the axles do not turn on either side. 

If you had the lockout hubs turned to "lock"......that tells me the lockout hubs are not working (probably just need to take them apart and clean them and relube them with a light coating of oil/grease).
With an open differential, if either front hub is not working, then 4x4 will not work (it will send power to the side that the hub is non-op on).

I should add that when I had the truck with all 4 wheels off  the ground, I started it and let the clutch out in 4WD.  The driveshaft turned but neither axle did.  When I turned the front driveshaft by hand in 2WD the right one turned and the left one didn't untill my buddy shoved in on the axle where it goes into the diff. Then it started turning. 

Sorry if I'm making this more confusing than it needs to be.  I hope it isn't the diff

When you were using 4x4 on the hill, if you didn't hear any noises from the front end, I'd say the front diff is fine.  I'd still take the hubs off and take them apart, clean them and relube them.  Even if they are working, it isn't going to hurt anything and should make them work smoothly and correctly for many years to come.

No noises from the frond end on the hill.  I have noticed for sometime now a click or pop when first engaging 4 WD but never any noises after the intial.

Two questions:

What year is this truck? If the truck is newer - it may have a vacuum-powered "locking" mechanism built into the front differential that does the same job as locking hub units.

Does it have locking hubs of any type?

Manuals are easy to spot.  Autos are the same size as manuals (without the handle on the hub face) and are bolted in place with 6 bolts.

More information please!

Thanks, ack for the reply. It is a 94 with auto locking hubs.   I  jacked all 4 wheels back up yesterday, started it up and let out the clutch.  At first the right axle was turning but not the wheel.  I then removed the right auto hub and noticed there was almost no grease in it and the little indexed tooth on the outer ring is broken off. All but a little nub remains.  I then put the right hub on the left side and vise versa.  Now the right wheel is spinning!  I stopped it by hand and now the left axle is spinning but not the wheel.  Gets confusing as to what I did after that but the point is I think the diff seems ok and one auto hub is probably bad.  I was even able to get the bad hub the grab for a moment by unbolting it and sliding it outward on the axle and holding it while the axle was spinning.  I then bolted it back in and it didn't work.  It needs replaced obviously but it would be nice to know exactly how these auto hubs activate.

The auto hubs are crap. Get yourself a decent set of manual hubs. Problems solved.

What year is this truck? If the truck is newer - it may have a vacuum-powered "locking" mechanism built into the front differential that does the same job as locking hub units.

None of the Sidekicks ever had a vacuum freewheel mechanism.  You're probably thinking of the 98~05 Vitaras & Grand Vitaras, and if that's the case, they did not use vacuum, the system requires air pressure to engage (~10 psi) and it's supplied from an air pump behind the front bumper.

Thanks, ack for the reply. It is a 94 with auto locking hubs.   I  jacked all 4 wheels back up yesterday, started it up and let out the clutch.  At first the right axle was turning but not the wheel.  I then removed the right auto hub and noticed there was almost no grease in it and the little indexed tooth on the outer ring is broken off. All but a little nub remains.  I then put the right hub on the left side and vise versa.  Now the right wheel is spinning!  I stopped it by hand and now the left axle is spinning but not the wheel.  Gets confusing as to what I did after that but the point is I think the diff seems ok and one auto hub is probably bad.  I was even able to get the bad hub the grab for a moment by unbolting it and sliding it outward on the axle and holding it while the axle was spinning.  I then bolted it back in and it didn't work.  It needs replaced obviously but it would be nice to know exactly how these auto hubs activate.

I found an explanation how auto hubs work at Ack's FAQ: do a search for  auto hubs.

I, like many other Suzuki offroaders do not recommend automatic locking hubs.  Yes, they allegedly make life "easier" when the weather is crappy and you need 4x4 traction.  Unfortunately, their ability to unlock when you drive in reverse
can cause problems.  The plastic parts inside tend to break - leaving you without a working hub.

As others have said, it is a good idea to swap them out with manual hubs.  You may get your feet wet or muddy, but you'll at least be able to get the traction you need.   The best prices are at pick-n-pull salvage yards!


I hope that this helps!

Thanks ack, I already order the manual hubs from a forum member.  They should be here tomorrow