I have 1991 HDJ 4.2 12V turbo with 35" tires and 3.727 ratio. I tought it is 4.10. But axle code K305 said it is 3.727. With 5 speed manual H151F. Now I am thinking add ARB front&rear air lockers RD132 and RD142 and pair it with 4.88. Or I should regear to 4.56... dilema... I would like to gain torque but not add to much rpm. I am not into top speed... It is not my dd, I use it for trips. In my country is a lot of hills and ups and down. If someone did it, please let me know