Ok so since i bought my truck ive had a kind of weird problem, basically, my 4x4 works, but once i go put it back into 2 the light will nooooot go off for like days, sometimes i cant even tell if it put back into 2 for a while... and another thing it does is, when i put the t-case into neutral or 4L, if i go to put it back into 2 it clunks and hits pretty hard back into 2, i had some vacuum lines on the t-case that rusted through and i just had them replaced and its still doing it, ideas?!

 

http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm

you could have a false light.
or you could have a sluggish disconnect.

 

so what would have to be replaced for the light to be fixed? the sensor on the t-case or something else?

 

start by locating the light switch on the drivers side end of the cad. disconnect and clean all the mud out of the connector. spray it all out with wd40. you can short the 2 pins in the plug to test the light in the cluster. you can test the switch with an ohmmeter.

the best way to test and solve cad problems is to put the truck up on 4 jack stands so you can crank it up, have and test vacuum, and see it go in/out of 4wd. if it won't shift in/out on stands, then it won't work right on the ground either.

you have to make sure the CAD/collar is sliding back and forth, and that the axle halves are locking up, and that the light is true.

when you get tired of fixing it, get a posi-lok.
http://www.4x4posi-lok.com/

 

Did you read the article DV posted for you or what?