Front axle issue on my 2008 LC120 – rear wheels spinning, need help

[Sivi]

I'm having an issue with one of my 2008 Land Cruiser LC120s (3.0 D-4D, automatic transmission, permanent 4WD), and I’m hoping someone here might have some advice or experience with this.

The problem is that it feels like the front axle disengages under load – even though this model has full-time 4WD. I own two LC120s, both maintained according to Toyota’s service schedule and running on the same type of tires.

• The one with the problem has 240,000 km.
• The other, which works perfectly, has 280,000 km.

The issue shows up on steep off-road terrain with rocks and roots, like natural steps. It’s dry terrain, not muddy or slippery, but rough and demanding – the kind of surface where proper 4WD is essential. When the problem occurs, the rear wheels spin, and it feels as if the front axle suddenly disengages, leaving the vehicle effectively rear-wheel drive.

Interestingly, if I engage the center differential lock, the problem does not occur – the front axle pulls normally, and the car climbs with no issue. Also, sometimes when I shift between L and 2, the front wheels start working again, but that workaround is unreliable and inconsistent.

I also tested the vehicle on a steep, linear muddy climb, where I could not reproduce the problem – the front axle engaged as expected and the car climbed without issues.

What I’ve tried so far:

• Compared both vehicles in the exact same conditions – only one has the issue.
• Used different gear positions and modes during testing.
• Checked for fault codes using a basic OBD scanner – no errors found.
• No warning lights or strange noises.
• Took the vehicle to an official Toyota service center, but they had no solution or explanation for the problem.

To me, it seems like the front axle intermittently disengages under load, unless the center diff is locked. I'm not sure if it's an actuator, transfer case issue, or something else.

I realize this forum is mostly focused on newer Land Cruisers, so if this post doesn't belong here due to the age of the vehicle, I completely understand – feel free to remove it.

Still, I’d really appreciate any suggestions or ideas – either on what to check next or where to turn for more help.

Thanks a lot!
Jack (Slovenia)