Would you believe we also live on 15 acres, in heavy hardwood forest, 1/2 mile from paved road, out in the country, 4 miles from civilization and our COLLIE is exactly like your GSD?
Our 5th pure-bred collie in 40 years - years ago all our dogs would run away and we refused to fence or chain them....dogs are meant to run free. Someone said, “Get a collie - they are home-bodies.” And it is true. All have been great watch-dogs but people-lovers.
None of our other collies were like this. This one barks when vehicles arrive, but is no problem - UNTIL vehicles want to leave. He then goes insane, thinking any vehicle here is now a part of his herd that he must control and keep from leaving! As any vehicle begins to leave, he almost rabidly will circle the vehicle, barking madly, even biting the vehicle occasionally. He even does this on all our vehicles that were here long before he was - he doesn’t seem to recognize them as belonging here - or maybe that they do belong and he cannot let them leave.
We have successfully trained him with a shock collar to NOT do this. BUT, the problem is he is too smart. Take the collar off of him - and he immediately knows, “Now I can do whatever I want...” and reverts to his old behavior.
So we restrain him or put him in the house when vehicles leave if his collar is not on him. I have his bite marks on my cars and motorcycles........
Damn, that sounds familiar.
You can buy a dummy collar that is a duplicate of the real thing except for the electronics.
Put that on him when the shock collar is charging.
If he is smart enough to tell which is which, put both on him at the same time for a month or so.
If he still outsmarts you, get two shock collars.
Most shock collar instructions I have read advise the new purchaser to use the lowest intensity to which the dog will react.
That is fine if you are teaching the dog to obey a command, such as getting him to c load in your car when you are ready to go home from a walk or hunting.
But when a dog is really excited, such as when fighting or chasing cars, he does not feel pain or any other stimulus the same as when he is calm.
When training not to bite, fight or chase you need to run the collar on the highest number and whack him immediately.
Also do not give any voice commands. You are not training him to listen yo your voice....you are training him to believe that the vehicle is punishing him.
And allowing a dog to run loose unsupervised, unless he is a hunting dog and you are in the field, is bad for the dog and shows a complete lack of understanding of animal management.