# 4x4 lock mode busted ( or worse ), need help in diagnosing



## Beaver (Jan 4, 2010)

2006 X-TRAIL automatic transmission / with 2X2 / AUTO / 4X4 LOCK / switch

Hello everyone, I wonder if there is some smart head around here that could give me some indication in 

what could I have busted in my x-trail. It's a weekend ,and I would like to gather some knowledge before taking the car to the garage tomorrow. 

Here's what happened:

did some light off-roading yesterday,
mostly easy trails with bumps and shallow paddles, 4X4 LOCK ENGAGED.

but then entered very sandy terrain, wet heavy sand since it was raining a lot lately.

first few climbs were very successful, I think with no wheel spin at all,
in fact I was quite amazed with the performance, I have contributed this to a light weight of the vehicle.
since I don't even have terrain tires on this thing.

then moved to a slightly steeper hills, where the sand was even deeper and heavier.

Car almost did it, but at the top of the hill, span wheels a little.
had about 3 approaches with wheel spinning at the top.

when climbed back down, suddenly I smelled burned rubber or plastic inside the cabin. Thought it was the tires.
Since heavy sand driving was over, I have switched back to AUTO , did again some easy forest driving, then hit paved road , then highway and headed back home. ( around 1 hour drive )

close to home , there is a trail but usually paddles are way too deep to go with the x-trail, so I have never tried them, this time just went there to check on how wet the trails were, and if there were any people.

I engaged 4x4 lock, carefully entered the trail ,I engaged 4x4 lock, carefully entered the trail, for just few meters, saw the paddles even deeper
so put in reverse and backed up out of the trail.

But now the car started to jump and squeal ( 4x4 LOCKED , and in reverse )
put in DRIVE, ( 4X4 LOCKED ) same thing. car skipps, and rough sounds I think from the rear, like something was holding one wheel.

2X2 MODE works just fine, did about 100 km hwy after the sand driving, and did not suspect anything. transmission works as usual in 2x2 mode

What did I bust ? a transmission? differential? rear axle?

Would anyone have a clue ?

I have read hundreds of related arcticles but never stumbled on a similar problem.

I will GREATLY appreciate your opinion or any input


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## tbk (Dec 29, 2008)

I am surprised no one has gotten back to you sooner. If I were you I would check out the australian xtrail site. What you are experiencing is what they often find on the sandy beachs in OZ. The 4wd does not like the heavy sand, and in all likelyhood you have overheated the transfer case or rear diff. Read the thread below for more info.

AUSTRALIAN X-TRAIL FORUM :: 4WD System & Transmission :: X-trail's 4wd system overheating problem ? ~ Runboard


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## Beaver (Jan 4, 2010)

Thank you, tbk, I'm aware of overheating problems, 
but my case is different. I have not experienced any flashing , no warnings.
Just smell of burned rubber, and from this point on when in 4x4 locked mode, I have a "chirp". 2WD is not affected. 
I was told by a mechanic that I need a new rear differential, but I'm not too sure, since this vehicle should simply disconnect 4x4 if it overheats, preventing from differential damage.. still searching.. but no answers..


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## tbk (Dec 29, 2008)

These vehicles do not have a limited slip, so if the car drives fine in 2wd mode, I can't see that you have differential problem. If anything it would be the transfer case. Probably a good first cheap start would be to have the transfer case oil changed, probably do the differential too for good measure. Have the mechanic take a good look at the oils to see if they appear burnt. This shouldnt cost more than a 100 bucks and should be done anyways.


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