we just recently got a new dog

First you have to convince him the leash does no harm. Take a short piece of leash and attach it to his collar. Let him carry that leash with him wherever he goes for a few days. Then slowly take the leash and try to convince him to follow you. Make sure you have something tasty in your pocket and reward him when he starts following you. If your other dog is good on the leash, the next step is to take him with you when you try to walk the new dog. Dogs do learn from each other. Good luck!

One of the dogs I have when I first got him hated being on a leash. I would put the leash on his and he'd either lie down and roll over on his belly or pretend he weighed 5,000 lbs. It was so bad that when people drove by and saw me taking him for a walk(or a tug -_-) I'd see people laughing and making comments. Eventually after regular attempts at taking him for a walks with little tugs when he decided he didn't want to my dog started to get the picture. Also I think you're at somewhat of an advantage having the other dog who is already trained. I got a second dog after he was trained. She would see the other dog behaving properly and learned several things just by coping him. I bet walking them both together might help the situation.