I have an 07 3500 laramie short bed single rear wheel. My four wheel drive isn't working and I don't know much about them. when I try to engage it the indicator light comes on, flashes then stays solid like normal but it sounds like maybe it isnt engaging fully. it's grinding somewhere and no pressure is being put to the front wheels. Wondering if its maybe just an actuator or something.

 

It sounds liked the actuator easy to check just pull the vacume line off it and make sure it has vacume if it does take it off the diff and make sure it is moving when engaged as well the lock in the diff is moving over the splines sometimes the rod on the actuator get bent and won't move ...just one of many things it could be but a start that is free to check....

 

Heh. Vacuum lines? My 86 W250 had vacuum lines. The new stuff doesn't, front axle is full time and the transfer case is electronic shift (or manual, but his sounds like it's a 273 like mine).

My 02 Dakota had the same basic setup, and the first time I needed 4wd it didn't work. IMHO if you don't use the electronic actuator periodically, it rusts/corrodes/gums up and fails.