After about an hour of searching, I came up with some info on the rear air.
Taken from a post made by Thai
From Toyota
:
A rear air suspension with X-REAS Sport Enhancement Suspension is available on Limited models with a V8 engine
for improved ride and performance when towing or hauling heavy loads. The air suspension uses linear height sensors to automatically adjust the ride height in accordance with the vehicle load.
My commentary:
The system will only raise if you have a heavy load...the degree to which it is raised is proportional to the load...thus, maintaining the same ride height as before the load (it keeps the 4runner level).
This is needed especially when towing. Because your 4runner is level, braking force is now evenly distributed. If your 4runner did not have this feature, the rear end will sag down, while the front will lift up. During braking, most of the braking power will be at the rear, not the front (due to sagging). With this autoleveling system, the braking will be distributed evenly (front will have more braking power). Of course, you will also have more steering control as your front wheels
are more "grounded."
And now from a post taken from specialist:
To the best of my knowledge the only way to "trick" the system is to put it at the desired height and pull the fuse. This locks it as its current height. I adjusted mine to be about an inch higher but if I put it in the highest setting and pulled the fuse I would about another inch and a half higher.
The taking the fuse thing out is interested. I'll have to look up which fuse it is, but I'll probably try that. What get's me, I know there is a reason Toyota has it go back to the middle position once 19mph is reached. Can anyone see any downsides to either taking out the fuse to lock it in the up position or to lifting the front and trying to get the rear to auto adjust? The problem I see is how the sensors actually work. I'm not sure if they check for lower than usual rear height (i.e. towing), or if they check for the vehicle being level (if so, we can lift and it'll auto adjust).
