I know it's "taboo" but I put 33x12.5 ATs on my 89 unmodified fj62.. for the first few months it drove like a dream.. now.. when I'm on the highway it seems to go in and out of overdrive.. I say this because of the sounds it makes.. I don't notice much if any change in the rpms but occasionally it sounds as though the engine is revving higher.. It will do so for a minute or so then the revving sound will cease.. I'm aware that when going to the 33's one should re-gear but i'm not totally convinced that this is my problem as it seems to do this from 50 all the way up to 70+.. any thoughts??