I'd catch him on the hop with very light, cheerful and friendly conversation especially the odd time you're alone with him in the office and want to cut right through that uncomfortable awkwardness. I'd chirp up with a bright and breezy “How are you finding and settling in the new job so far? Not easy being the new person no matter what and I'm sure you don't need it but if there's anything I can help you with or you're not sure about give me a yell any time. OK I'm gonna make myself a brew do you want one whilst I'm there?”
It might be that he's just socially awkward and not good at breaking the ice and getting those initial chit-chat conversations started but if he is, you'll know from his reaction to you being warm and friendly.
If he's still a sour puss grumpy faced sulking sort you know it's his issue – not yours. You've made the effort and gave him a warm welcome letting him know if he needs anything he can ask you no bother.
The more I feel someone is making an effort not to talk to me or has decided already they don't and won't ever like me, the brighter, breezier and harder I make it for them to sustain it. I once took over as the new manger in a care unit that until then had been run entirely by and for the convenience of staff and they had all decided before even laying eyes on me that I was the devil, they would never like or respect me as the new boss and no matter what anyone says they did not consider themselves answerable to me.
I knew they were all at it and quietly carried on like I had no idea and had shit for brains. Tickled me the way one girl got visibly angry at letting her guard down and losing focus when she engaged and had the odd moment of an actual friendly back and forth conversation.
The OP did remind me of a bloke that was very similar going out of his way never to be standing directly alongside or near to me when in the room. If I was sitting down he had to stand up almost looming over me with his manliness. If I was standing up when he was sitting, he got up but moved to the other side and crouched or leaned oddly against the wall or furniture.
Clocked what it was all about eventually. I'm tall and at just over 5'11 was very slightly taller than he and he didn't want it to be made obvious by allowing us to stand tall side by side. Some men just have an inherent belief and genuinely think women are pathetic creatures and incapable of anything. Others know different but find it threatening so try to assert themselves and feel more confident by bringing out their manliness and showing us how it's done. Sad really.
I had one of my dogs with me one day when he rocked up and remember her wiggling and wagging her tail excitedly and I went “Come here daft sod sit yourself down” and she carried on with super excited wagging cos she loves meeting new people.
He gave a low loud manly “Sit down” and she sat down still wagging her tail on the floor. Really properly pleased with himself and did a shoulder shrug kind of thing See? That's why men make better dog trainers and handlers they know how to command respect. You women are too soft I mean not even yours take a blind bit of notice but it knows different when I say summat!
Me “Yeah? Maybe I dunno... Dog. Watch him” Dog pinned and fixed her eyes on him cos she's done protection training and knows “Watch him / them” means do not take your eyes off that person and if they move back them up again don't let them shift from outside this space unless and until I say.
He shit his pants. “Get out g'on giddout of it ya bad bugger!!!”
Me “OK that'll do sweet. Come here good girl” and she went right back to wagging and arse wiggling cos she was now able to meet and make a new friend.
He was so up his own arse that he really thought her sitting down when he bellowed "sit down" was because she respected him more and he was therefore best placed to tell me the ways of the force and teach me all I need to know.
Can't imagine show exhausting life must be for someone like that. How do they get through a day??
No matter which side your new manager falls you'll at least know any further issues or problems that crop up aren't on account of anything you did wrong.