the truck barking thread got me thinking that i can get some advise from you all as well. first my dog is a fila mastiff and not a gundog, he hates guns as well as swimming or retrieving. nonetheless he goes with me quite a bit and his/my problem is if i leave him in the back of the truck by himself he barks. he barks for hours if need be. ive been told that i couldnt bring him to work and leave him in the back of my truck because of his barking and i work construction. shock collar, he dont care he still barks. if i tell him to be quiet and walk up to the truck to scold him he cowers and takes his verbal assault and waits till im about 30 feet away and starts to bark. no problems enroute just when hes left alone. any suggestions?