This sounds familiar...my 3 year old daughter has trouble keeping her hands to herself as well and her daycare is concerned about her "odd" behaviors and her sometimes being uncontrollable because she doesn't want to participate with the other children and she throws tantrums and they are unable to calm her. She also doesn't hold conversations she just repeats things. She curretly she's a neurologist for her epilepsy and he suggests that she could have, ocd or some type of autism. I have made her an appointment to see a pediatric psy. doctor who if there's something wrong he would be the one to diagnose her and she will also be visited at daycare by a team from the public school system (consisting of a behavioral specialist and a speech therapist). So now I just wait and see what the outcome is of these elvaluations. Hang in there and definatley seek all resources to help your son and get hoom the help he needs. good luck to you!
From the information you provided, I'm not immediately struck by the probability of learning disability (unless it's in the area of auditory processing). What's more striking is possible attentional deficit coupled with hyperactivity syndrome. But remember - he's not even four yet. Three- and four-year-olds are famous for being quite active and impulsive, and for displaying limited attention. They are young, after all. Now, even in some very young children, the degree of overactivity, impulsivity and inattention can be beyond the norm. The move to the smaller class sounds very prudent, and it is worth having a talk with the doctor and gain his/her perspective. ADHD can be diagnosed in pre-school children, but be careful to go about the evaluation in a systematic, thorough fashion - don't jump to conclusions or rush to a premature diagnosis.