I have a 1990 Jeep Wrangler. I have a hard time getting the Jeep into 1st gear or reverse. Reverse will grind and first is difficult to get into when I am sitting at a set of lights. I do have some luck on both first and reverse when I go into third or fourth gear and then go into first or reverse. I just changed the transmission fluid (SAE 75W-90) but that only helped slightly. Once I am going it shifts fine. Any ideas out there. I appreciate.