I'll echo what Splicer said... Shifting in/out of 4hi you want to be going straight and under no load on the drivetrain. Usually I'll be rolling along foot off gas or constant speed. But even stopped with wheels straight should shift ok, but a slight thunk once and a while does happen.
Keep trying it, I'll go in/out easier the more its used.
Keep trying it, I'll go in/out easier the more its used.
