Alright I have a 1997 f150 lariat 4x4 and the 4x4 is acting funny. What happens when I put it in 4H it starts to bang a lot and then it starts to wine and has a hard time going through the gears. To get it to come out of 4x4 I have to turn the truck off then turn it back on. I took the truck to the local for dealership And they hooked it up to their computer and said nothing was wrong with the truck but it's still has 4x4 problems. I don't know where to look to solve this problem. Need much help!

 

Sounds like pure incompetence to me.
You need to know how the system works too recognize where the operation goes into trouble.
Lets start by going to the transfer case motor part of the operation.
Does the noise sound like gears grinding at the transmission area?
Does the noise seem to come from the front axle?
Your going to have to pay attention to this because they are two different places and you have not given any hint of that. It's important.
Good luck.

 

It does sound like gears grinding and yes it sounds like it's coming from right under the cab.

 

You have to investigate to be sure which location.
The reason is the transfer case motor engages the transmission drive train.
After that, the driver side front axle is coupled by a sliding link done by a Vacuum driven Actuator.

Try this; engage 4H while sitting still.
Does it go in and move the truck without a problem? noise , binding etc.
.
Think the following;
1. The case motor engages the gear train and syncs them while moving, with an electric clutch. It's located on the back of the Transfer case.
2. The front axle will try to engage a spline in each shaft. If it does not you will hear it as a specific noise. The Actuator is under the Black plastic cover up in the area where you would get to the Oil filter.
That's all I can help you from here.
You have to do the rest.
You can see from this that just looking for codes and saying nothing is wrong don't cut it.
Good luck.