difficulties with change is a huge part of autism for many autists,and it can vary from a little dislike up without any reaction to full blown violent fight [or flight] reactions to the smallest changes to someones environment,the people around them or routine.
difficulties with change in autism only,is very different compared to difficulties with change in OCD though a lot of autists all over the spectrum have OCD ontop of their ASD as it originaly gives them some control and predictibility but then becomes an out of control mind torturing disorder.
change with autism is much easier to cope with if there is advance given on the change,and if the timeline/PECS and transitions are used,fight or flight reactions are guaranteed for many of us when it comes to change with no warning whatsoever though as it is a trigger of the stress chemicals which is what fuels fight or flight and makes someone rage and seem like they have super strenth,or run from the problem.
change difficulties in OCD only is about the fear of something bad happening if a person doesnt do what they are being driven to do.
they may know nothing will happen but their mind is painfuly controlling them to do something and they wont stop being harassed until they give in.
a very bad OCD trait of mine is with turning all switches off and making sure doors are locked at night and will go over and over and over this,have done it since little and it started because used to watch dad doing it,though luckily, guess due to the autism it is only associated with at mums/dads and do not have this routine else where,no way to describe it other than it being extremely painful in head.
OCDs effect on change in autism makes a person very fearful or even phobic of change.
people who have moderate/severe/profound autism quite often have OCD or OCD traits as a reaction to change and unpredictibility,but it is usualy labeled under their autism and not seen as an issue that can be helped.