I have a 2007 Dakota 4X4 and one of the 4wd settings is 4 lock. What is that?

 

4WD Low

 

its 2wd/ 4 lock/ 4wd low/

4 lock is 4wd high

 

Dakkkota is correct, 4Lock is 4wd high.

All 4 wheels are turning at the same speed, DO NOT use 4Lock on dry pavement!

 

4 lock is best used on roads with loose condition snow gravel ice (it will not help you stop) it will give you traction to get moving. if you an an average driver to work home mall on the weekends. chances are you will never need to use 4low its a lower gearing to give you more torque to pull you through ie. really steep loose condition hills really deep snow and mud. it'll help keep your tires from spinning keeping traction. the second your tires spin your loosing traction. if your curious find an open field and put er in 4low and give the gas a tap your not gonna go very fast but you'll feel a lot more power

 

It is really confusing and adds no value IMHO.
The way I have heard it explained is that the "lock" means that the transfer case is locked (as opposed to the vehicles with all wheel drive where it is allowed some slippage to prevent it from damaging itself on normal dry roads.)
Be aware that even though the transfer case is locked you can still end up with only 2 wheels spinning (one front and one rear) if you don't have limited slip or locking differentials.

 

what happen inside the diff when switch to 4wd low ou high?

same as rubicon??? magnet?

 

im not sure but its prolly not the same as the rubies they have a true locking diff where as we at best have limited slip