Auto Locking Hubs

Try changing the oil to a good synthetic gear oil ?
The oil may be too thick when cold causing the shaft to turn . Just a guess as i'm not familiar with the internals on the nissan.Life is short- but there's always time for a yarda.

Stu,
That model uses Automatic transmission fluid in the transfer case for that reason...
On manual hub models it is not a problem using heavier oil, however on auto hubs it is a problem as the drag from the heavier oil when cold is enough to engage the hubs.
Change the transfer case oil to Dextron3 and your problem will be solved.
Will

Hi there,

I recently diagnosed a similar problem with a 98 GU 2.8. I found that when we put the truck entirely on chassis-stands, the front prop shaft moved. WHen compared to my GUII 3.0, the shaft did the same. A measure of the load indicated that there was only just enough to rotate the shaft and that when you applied some friction to the shaft, (wrapping a cloth around it and pull tight to act as a brake - NEVER use anything you can't afford to loose - such as your hands!) the shaft stops moving.

I put this to the fact that Nissan TX12A has a syncro ring, sleeves and a set of keys that retain the drive sprocket. What you do to engage 4x4 is to pull the syncro ring, that engages to the clutch gear.

What you may have is a sticky syncro unit on the mainshaft that connects to the front-wheel chain. Alternatively, your selector system is maladjusted or faulty and is resting on the syncro just enough to put some power through.

This would be the only way that you would be getting drive to the front. Again, more examination is needed! Try flushing the box out, using a lighter grade of oil (Although you should use DexIII) and change your fluids every 20 thousand.

Regards,

ChrisFord.

Stu,
In my opinion if they are the auto locking hubs with the nut head in the centre ditch them they are more trouble than they are worth, the manual locking hubs are a straight swap and cheaper to boot. My mate converted his after breaking two sets of hubs, hasn't had any problems since. My opinion as usual people.Keep the shiny side up

Auto hubs are also bad for 4x4ing.

When I go 4x4ing. I get my tyre change lever (socket type) and put them on 'LOCK' all the time due to the fact that the 'auto' mode unlocks itself when reversing downhill when its on 4x4 mode. (potentially dangerous)

Once I didnt know about this until someone told me, I was climbing up a hill called 'telecom hill' at landcruiser mountain park only to find that one rut was a tad too deep, 'no worries' I thought..... reverse, and go back a bit only to find that I was in 2WD and the rear tyres were scraping backwards - It gave me a scare, but due to previous experience I knew how to stop the car by stallin it and gettin mates out to lock the wheels in.

Unless you dont like changing the manual hubs all the time like the rest of us do, then most likely you'll have to do it 'manually' as well for your own safety.

Regards
Tom

Ah thank God some else has posted this problem, I wasn't sure how to word it.
Mine does the same thing so I changed my Hubs (95 model) to manual ones but alas the bleep ty sound was still there on and off. I was gonna get around to putting the car up on blocks and sticking my head under as I suspected the transfer case was slipping into 4wd and turning the front drive shaft with a chattering sound/feel. Someone said it may need adjusting, is this true as i'm a bit worried about expensive repairs. The car has done about 270,000k's and has a good service history, though I don't know when the gearbox/ transfer case oil was last changed(also on my to do list).
Any tips on how to adjust/fix the prob. and what oil are you guys running?
Thanks Scott