was a cool day at work ,so we jumped in the truck to get warm,revved it up on 2003 Dodge Ram 2500

revving it at 1500 to get heat .truck was in park and we got a strong burning smell and smoke.turned out to be tranny.tranny guy says this happens allot ,it took out reverse,try to go forward in reverse.has this happened or has anyone else heard of this .and is it true you can't rev them in park,doesn't sound right to me .