So I put a cummins into this 92 sd had 460 . It has 4.63 gears. I was told by previous owner that it had been doing this for a while. How do I fix this? Also omg 4.63 sucks and open dif sucks . So Detroit is in future. And what gears would be best. 3.73 or 3.54 it is a 5 speed with dump bed.