Dealing with Power Struggles in 3 Year Old

he sounds like an unusually difficult little guy for sure, at an age when most are difficult anyway.
let the pjs go. he needs a pullup but not pajamas.
try giving him a choice between diapers or pullups, or something to that effect. choices make angry powerless little people feel as if they at least have a say.
stop spanking him. spanking will not make a furious child less furious.
talking to him won't help either. when he's screaming and banging he's not listening.
time-outs need to be tweaked. what does he like at bedtime? stories? singing? cuddles?
take him to his room and give him a choice of diapers. if he screams, go out of the room and close the door and let him scream. don't yell, don't engage, don't talk at all. don't come back until he's quiet.
i dunno, i might even consider rubber sheets and no pants until this phase is worked out. better to deal with wet sheets than a wrecked little person (not to mention your own psyche.)
with stubborn little guys this age i treat them like i would a young horse. the less you give them to resist, the fewer battles you have overall.
khairete
S.

One of mine went through a tantrum phase. In our case, he was having trouble communicating. I learned some really helpful techniques on how to head off tantrums though at this age.

One is to give plenty of warning - and do things ahead of time. Be proactive to preempt the behavior.

I would get my little guy ready for bed way early. So let's get our pajamas on and teeth brushed, then we'll play forts ... etc. Fed him well before he got cranky. Left malls before he started to get antsy. Small manageable chunks of time.

Took many mommy minutes (time out for me). Swapped with my husband. Stayed calm - they are freaked out they are having a tantrum, so spanking them or losing it yourself just makes it that much worse. I never restrained him or spanked - I just would walk into the next room and say I'm just going to be over here until you calm down .. eventually he'd tire himself out - then lots of hugs. But mostly a lot of praise for when he worked with us and was cooperative. He outgrew the tantrums and in our case, helping him over his communication issues helped the most.

try giving him 2 options and let him do the work. diaper or pullup? pajamas or t-shirt and shorts/pants?
have him pick whats worn, it gives him the controll that he desires, and since your picking the options its giving you controll too. also give him a natural consequences night. he refuses the pullup? let him sleep bare butt so he can see what happens if no pullup or diaper is worn. if hes refusing the pj's let him sleep without anything, if hes too hot while sleeping he may do better without wearing anything, or he may get too cold and realize that pj's keep him warm.

If the bedtime thing is recent, reconsider the pajamas. There might be something about them that he hates, but he can't tell you. Itchy, too tight, a poky tag, etc. Try ditching the PJs and see if he does better in the kind of clothes he wears during the day.

2kidmama's is right about being calm. Even when you're not, try hard to project that you're calm and in control. Take action, but don't be reactive.

Can he talk?
If he can't communicate, all he is is frustrated. That needs to be addressed before anything else if it hasn't been already.

Get him assessed through Early Intervention in your school district and try to find out if anything is going on sensory-wise, processing wise, whatever.

If he can communicate, or if he can't communicate but CAN understand, talk to him when he's NOT upset about these things and see if you can figure out what might be going on. He might be able to show you, or something or at least give a clue as to why he gets upset.

I can assure you, he doesn't want to be this stressed either. Finding ways to help him communicate what's going on, whatever tool that might be, is going to help a lot, hopefully.

Hey A., sounds like your little man has some strong opinions and feelings that he is not being able to communicate well. He is quite literally "acting out". He needs your help developing his communication skills and his eq, so that he can effectively communicate his needs and opinions without head-banging and thrashing. A few tips would be to:
1. Help him to realize that communicating respectfully is going to be the must effective means of communication, by only rewarding his proper communication responses with action. So when he asks for something nicely, if it's a reasonable request, do your best to fulfill it, and let him know that you appreciated how nicely he asked. If on the other hand he did not ask nicely, nothing moves forward until he does so. You need to help him understand that head-banging, thrashing, crying etc are not appropriate means of communication. So for example: he starts screaming for a toy that's out of his reach. Acknowledge what he wants in as few words as possible "the red ball" and then when he says yes, tell him you will happily help him get it but he has to ask nicely first. Screaming for it or throwing a fit is not nice. And then, calmly hold your ground. He needs to understand that his actions of fit throwing will not only not move you to helping him achieve his goal, but they will also not move you to loose your temper or ignore him. He needs to be able to see you handling frustrating situations calmly and fairly. This will not only be a good example to him of proper communication(specifically you don't fly apart, use violence, or treat someone poorly when they don't act in the way you want them to), but it will pay dividends in your relationship with each other, and in helping him to develop self-control in general. This needs to be carried out in a way that's due not punitive, it is you patiently teaching him a very important skill set.
And the second tip would be to maybe re-access your night time routine, with your son. It doesn't sound like it's working for you all. So maybe sit down with him, when you to are both calm and connected with each other, and tell him that it makes you sad that he gets so upset at bedtime, and you want to make it better for him. Ask him what he likes about bedtime, or what he would like to do before bedtime. Explain the things that need to happen at bedtime (pull-up, brushing teeth, etc) and ask him how you can help make those things better for him. So maybe you can take him to the store and let him pick out the pull-ups he likes with Winnie the Pooh on them or maybe he would prefer to wear diapers. After you have compiled the list of to-dos for bedtime, teeth brushing, pajamas, story and being tucked in, put them into a set and agreed upon order. When it comes time to begin the routine, help him to focus on the process itself and the aspects of the process he enjoys like the story or being tucked in, and then, if you can find a way to turn the parts that he doesn't love into a game. For instance my son hated brushing his teeth, so I began telling him there were monkeys in there, I had to get them out, and making monkey noises while we brushed. He howls with laughter and asks me to get the monkeys out several times a day now.
My third and final tip is a little bit of a shameless plug, but I actually have a Udemy course specifically on tantrums. It's called: How to Quickly Stop or Prevent Tantrums. And you can use the coupon code: MAMAPEDIA2016 to get half off.
Good luck to you and your little guy. Just remember, you and your sons father are the two people in the best position to help your son. You know him better than anyone, and even though it's definitely challenging at times, no expert, book, or Mamapedia member loves him like you do. You've got this!

So hard! Hang in there...you will get through this. My son did this at that age too. It helps to be super calm and talk in a quiet calm voice. I would have to physically place our son in his room and tell him he could come out when he was calm. He would get so out of control. He also would head bang, throw stuff, kick the door until he reached a point of exhaustion. Ignore the tantrums as much as you can. Just walk around him and don't give the tantrum attention. It's so hard and stressful but remember he will mature and outgrow this. The key is for you to not take it personally and stay calm. My daughter never did this...she has a much easier personality and wants to please adults.

It's interesting that the school has seen no problems with tantrums or screaming. I'm wondering about the bedtime routine.

Is it possible that he's hungry at bedtime? My daughter used to get terribly frantic and upset when her blood sugar was low, and I'd give her a protein snack and it would help calm her. So I'm wondering if there's a connection between food and his anxiety at bedtime. Maybe he's getting food at more regular intervals in school?

What time does he eat supper, and how is his appetite? What kind of meals does he eat, at school vs at home? How long is the period of time between supper and bedtime? Maybe a protein snack before the pull-ups tantrum would help, like string cheese, or a good quality yogurt (not the rainbow colored kids' junk with sugar, but plain Greek yogurt with something fun added to it like cut-up berries, or a little all-natural jam stirred in, or even some mini M&Ms sprinkled on), or peanut butter on apple slices, or toast with peanut butter, or toast with cheese melted on top?

He has something going on that probably needs intervention. I'd say he's ODD and possibly has more. Please contact the agency that did your evals for speech therapy and to get him in that preschool. If they can't help them find a local children's hospital and ask them to switch your call to the evaluation team office, team that helps diagnose disabilities in children. They should be able to help you after an in depth eval and get you on the right path.