Inter Axle Diff

Depends on what kind of surface you are driving on. If you are going to be running on a surface where you don't need to use to the power divider for better traction, you should disengage it. If you leave it engaged on surfaces with good grip it will put extra stress on the drivetrain which you don't want. If you're running on a surface with poor traction, even for an extended period of time, then you can leave it locked in. But any time you're gonna hit a surface where you wouldn't normally need it, disengage it. Always wait until all axles are turning at the same speed before engaging it, trying to lock it in with the axles turning at different speeds (especially when one axle is spinning) can really cause damage.

Bottom line, use it when you need to, disengage it when you don't!

 

Short answer , hmmmmm. Nope . I have driven out of the mud and forgot it for several hundred miles. Never had an issue.

It is certainly not a good idea, but it happens. The adverse effect it has on steering is the worst part, tends to push thru the corners.

 

It will wear out your drive tires in short order if you leave it on while driving on surfaces with good traction.

 

A lot of newer trucks will disengage diff locks above a certain speed .. Main issues would be tire wear higher temperatures and maybe a bit more driveline stress I'm guessing

 

If your tires are matching, you can get away with it for a little longer than if you're not, but it's not recommended for hard surfaces for pretty much the same reason you're not supposed to keep a transfer case on a 4x4 engaged on hardball surfaces. If you're running an older set which are worn down more on one axle, it adds stress to your driveline and also will wear down your tires.
The power divider is always providing power to both axles... however, in the unlocked position, it allows the outputs to turn at different speeds. This is why you can have a set of tires at, for example, 13/32nds on one axle and a new set of tires on the other and not tear them out. Locking it locks both output shafts to rotate at the same speed.