Barking is improved because you are tying the larger front discs and calipers to the smaller rear ones. The effect is that some of the front breaking force is transferred to the rear wheels.
In my old defenders if I had to do an emergency stop, especially with a trailer on I would instinctively slap the T case into locked. It definitely shortened the stoping distance. It saved me rear ending someone on at least a couple of occasions. I have never done it in the Grenadier partly because it has ABS and pretty good brakes, and partly because I'm a more sensible driver these days. A defender with no ABS will lock the front wheels long before the rears, Locking the CDL prevents this.
In terms of handling I'm not sure of the science, ASPW did a video on it once where they put a 4x4 on a skid pan with a trailer, it handled much better in 4wd.
By far the biggest reason to lock the CDL off road however is if you have to reverse down a steep slippery hill, (think failed hill climb) 10x this if you are towing.
When pointing uphill there's less weight on the front wheels, which is the opposite of hard braking when going forward where more weight is added to the front wheels. This lack of weight results in a lack of grip. So on a reverse decent light braking will still result in front wheel lockup, or acceleration if you have ABS as the ABS will be off more than its on. Locked front wheels can't steer and you end up with a very uncontrolled decent, potentially sliding sideways and rolling. Or a jack knifed trailer..
I'll try and find the video from Lord White.
In my old defenders if I had to do an emergency stop, especially with a trailer on I would instinctively slap the T case into locked. It definitely shortened the stoping distance. It saved me rear ending someone on at least a couple of occasions. I have never done it in the Grenadier partly because it has ABS and pretty good brakes, and partly because I'm a more sensible driver these days. A defender with no ABS will lock the front wheels long before the rears, Locking the CDL prevents this.
In terms of handling I'm not sure of the science, ASPW did a video on it once where they put a 4x4 on a skid pan with a trailer, it handled much better in 4wd.
By far the biggest reason to lock the CDL off road however is if you have to reverse down a steep slippery hill, (think failed hill climb) 10x this if you are towing.
When pointing uphill there's less weight on the front wheels, which is the opposite of hard braking when going forward where more weight is added to the front wheels. This lack of weight results in a lack of grip. So on a reverse decent light braking will still result in front wheel lockup, or acceleration if you have ABS as the ABS will be off more than its on. Locked front wheels can't steer and you end up with a very uncontrolled decent, potentially sliding sideways and rolling. Or a jack knifed trailer..
I'll try and find the video from Lord White.
