I been looking around alot and hard to find a consitant answer. Im runing 39.5's and looking to maybe upgrade gears soon. From what I hear 4.88 is my best bet. My question is what will be the benifit of getting new gears, right now im kind of slugish on freeway im hoping that would fix that and hopefully get better gas milage. My MPG has gone to **** since the lift and tires, dont get me wrong I expected it but it seems worse then I thought. Any help is appreciated, thanks.

 

4.88 is your best bet, 5.13 would be to steep and 4.56 wouldnt be enough for 39.5" tires. The benefit would be more bottom end as well as keeping your RPM's up through your power range. Good lookin truck too!!!

 

I am also in the a search for a good/proper gear ratio. I was talking to another member on here and he had suggested to me to run a 4.88 in my truck 01 Screw 5.4 4x4 Auto. I do only have 35/12.50/16's but he had a set of 4.56's with the same tire size as mine and took them out shortly after due to the ratio not being up to par on performance kinda just brought it back to a mild stock rating if you will. He put 4.88's in and was very pleased. He also had mentioned that it was good to have the 4.88's due to the fact that he was going to be putting 38's or 39's on his truck and that was the gear his buddy had in his truck with the 38's and that ratio was working very well for performance and power. One more thing he had metioned that may or may not help is that he was turning 2700-2800 rpms at 80 mph on the hwy with the 35's on the 4.56 ratio.

 

4.88, would put your tranny back in the optimum range it was meant for. your MPG will greatly improve, and it will take allot less throttle to get it to speed. i highly recomend regearing, it will save your tranny in the long run also. good luck