hi everyone, i am new in the jeep field, i have a 79 cj5, the problem is that it has 35's and i have problems when going uphill (loss of power)it has the stock 258 with a 3 speed transmision, with a dana 30 front and amc20 rear, i read that differentials ratio is very important on this issue, but the jeep came as it is, how can i know what are the differential relations and what ratio do you recommend, i thinking to switch to 33,s. pleaso somebody help me!! totally lost!!

Hi, If I was in you're shoes i would start looking for a dana44 rear axil if you are going to do any offroading. If you put a locker in the amc20 it is a mater of when and not if it will fail. but that is my owne opinion. now enough of my ranting and to you're question. as for a (gear ratio to tire size) chart Idon't know of any.But 4.11 gears would probobly do you fine for 33 in tires, but with 35in.tires you should probobly go with 4.56 gears. What ever you do keep in mind you have to do both axles with the same gear ratio and since you are doing it a rear axil upgrade and a locker is a good idea if you do any offroading.I hope i helped and good luck with you,re jeep. lash OIIIO  

my guess is that you need 456/410 gears with the 6 cylinder engine