Goes in to four wheel drive but front tires are

you need to stop both front wheels from turning to see if 4 wd is working
just stopping one side means nothing as the diff action is operating and making the opposite wheel go faster

This is some what normal for front wheel drive and four wheel drive, when it's in four whell drive. I would check the swaybar links and traction bar. both in the front of the vehicle. Sway bar goes from tire to tire mounted to the lower control arms. and traction goes from one tire to just past center, mounted to the frame.

Hi,
Yes, this is normal while in four wheel drive on pavement.
I will try and explain why.
In four wheel drive the front and rear drive axles are linked together by a chain in the transfer case and gears in both axles. This is a direct link with very little play between the front and rear axles.
When cornering a rear wheel will spin faster, or slower depending on the direction of the turn. this causes a binding in the drive line because the drive line wants all the wheels to turn at the same speed. So the wheel "skipping" going in reverse, is the drive lines way of compensating for the different speed of the wheels turning.
Never should a four wheel drive be used on dry pavement. I could cause a break in one of the drive line components. On a slippery surface , snow, mud, gravel, grass, There is enough slippage in the surface to aloow the driveline to compensate for the different speeds of tire rotation.
So do not try at highway speeds on dry pavement.
Your four wheel drive system is working just fine.
Wayne

As this car IS a FRONT wheel drive, that is switchable to four wheel drive (it switches off at 21 mph)if when you switch to 4wd and your fronts have no drive,the drive automatically goes to the wheels with traction(rear)try putting the rears on wet grass and see if you move when you hit the gas........hard.

there are vacum line one on each side behide the wheels see if they are broke or leaking i had the same problem

Check for a vacuum leak under the hood. The four wheel drive front hubs are accuated by vacuum.

A Dodge Dakota with 4-wheel steer? Do you happen to mean 4-wheel drive?

If so, you should not operate the vehicle in 4-wheel drive when you are traveling on a hard, high-traction surface. When in 4x4, the transfer case connects the front and rear axles, and does not allow for differentiation of wheel speeds necessary when turning. This is compensated for when driving over low-traction terrain because the tires slip easier.

Basically, the jerking, bucking and locking of the truck is due to the binding. This will eventually lead to damage in the driveline. If the roadway isn't covered in snow, there is no need for the 4 wheel drive to be engaged.

the front hubs aren't locking. try replacing with WARN industries manual locking hubs. the auto hubs slip out a lot

small vacum hose i replaced it twice and will have to do it again it seems to happen about every two years after five years of age

Vacume line is leaking and do not engaga fully. Vacume pipe an front wheels. 2 pipes 1 for brakes 1 for vacume. Pipe (rubber) connect by means of pushing it over the steel pipe. Easy to replace. Willem SA