Wasn't totally sure where to post this. I have a '91 4runner. Its a solid truck, runs well. Its been well maintained. It just has some trouble when climbing hills. I've found that if I shift it to 2nd gear and keep it there, the truck has less trouble climbing the hill, but when left to the automatic transmission it really struggles and doesn't shift when it should. Does this sound familiar to anyone? Is there anything I can do to the transmission to help this problem? I realize it's an old truck, but I think this is something I can look into. Any help would be great. Thanks!