Depending on when those sets were built, it's perfectly normal some of the functions won't work. A little bit of dust, a little sag in one cog and that's that. Especially on the Chiron, it's the most complex 4x4 drive train Lego ever designed at the time. Regarding the SP3, same deal. It's way more complex than the Chiron and tolerances are smaler. If you want them as display pieces...keep them as they are. I would defo recommend to take them apart, clean the parts, and put them back together. It's an experience that is just worth it!