[fordem]

First - I'm not asking if air lockers can co-exist with traction control, the answer to that is they can, the traction control system will just not sense that there is a loss of traction on that axle, as both wheels will be turning at the same speed. I'm also not looking for an air locker VS traction control discussion, the traction control system needs to sense wheel spin before it will brake the spinning wheel making it a reactive intervention and not a proactive system.

What I am curious about is how the two interact on a loose surface, for example, loosely bound gravel or laterite surfaces - on surfaces of this nature, running in 4H (part time 4WD, no center differential), you can quite often just point the truck where you want to go and allow the traction control system to manage itself - it will brake which ever wheel is necessary to keep the truck moving in the direction the front wheels are pointing in.

Theoretically, in a situation such as this, having the rear differential locked would/could change the dynamics of the situation - not only causing one or both rear wheels to loose traction, but also preventing the traction control system from sensing it & correcting it, and possibly further compromising the vehicle stability by "blinding" the traction control system to what the rear end is actually doing.

Maybe the solution is as simple as not engaging the air locker on a surface of this type, or at this speed (> 60~80kmh).

What are your thoughts?

Vehicle in question is a Suzuki Jimny XL that has not yet been purchased (the first ones are expected here in June), and the "consideration" is whether or not I want to fit an air locker in the rear.

[Gwagensteve]

Whilst I can't really speculate* on the effect on the stability control system (because that's really going to be what's driving the ship at those speeds) I can say I wouldn't be driving with the locker engaged at 60-80km/h.

*but for poos and giggles, I'll try. Driving with the rear end locked at those speeds will make the car very tail happy. When the car senses that much lateral movement and different wheelspeeds front to rear, it will kill the party.

[fordem]

Thanks Steve, I was focused more on wheel speed side~side, and did not consider front~rear or the yaw sensor.

[SPEEDY]

I'm not sure that running a locker at speed for an extended period of time would be a good idea. Generally speaking when I've used lockers it's only been for short periods of time when needed, then turned off.
I have engaged it for a bit of wheel spin fun in the dirt, but thats a rare exception.
While I'm sure it would work, I'm also sure it would end up damaging something expensive in the drive train.
Another problem I had with a Sierra that had a LSD with very little slip in it was that it was next to suicidal on wet tar and dirt roads. On steep inclines in those conditions I had to take off in 2nd gear, otherwise the wheels just spun in place. Worse yet was corners, a few times around corners, or taking off at lights and changing gears I'd end up facing the direction I just came from
That was a light rig with reduction gearing and 31" mud tyres on it, so that amplified the problem, but it also demonstrates a risk that might otherwise go unconsidered.
It comes down to it while it's entirely possible and would probably work, it's still not a very good idea.

[Gwagensteve]

Many sierras have run mini spool or welded diffs for years. (Including mine for something like 15 years) and whilst understeer on corner entry and oversteer on corner exit is increased it’s pretty easy to adapt. It’s certainly not “suicidal”

Many people have the opinion that a welded/spooled rear diff is superior to an auto locker in terms of road manners.

At road speeds there isn’t enough torque being generated to break axles and no other driveline part is affected by the diff being locked or not, so I don’t know which expensive driveline parts would be damaged by having a locked diff at road speeds. Again, also not my experience.

The issue is in relation to how a locked diff interferes with traction or stability control and speed.

[SPEEDY]

I ran 3 before it with similar set ups but this one was, they were all a little tail happy when you planted your foot on a corner, but this one was my 1st soft top, with the rear seats removed, it had no weight on the rear wheels, with 31" muddies and that diff and gearing it was a monster in the wet.
I did get used to it, but after driving a more sedate Nissan patrol before buying it, there were some pants staining moments in it when the roads were wet until I did get used to how to drive it.
That one was an extreme example, but it is something to be aware of if your going to drive with a diff lock engaged on a loose surface road.