Axle gearing

I own a 1975 CJ-5 with a fiberglass body,a 5.7 TBI Chevy engine and T 150 trans and model 20 transfer case. I have 3.73s in my differentials and 31x10.50 15 Super Swampers. On the highway the gearing seems too low. What should my gearing be for daily commuting and weekend wheeling?  

do you have a tachometer???

is your transmission transfer case final drive ratio 1 to 1..??


seems you might be running with that tire size about 2450 RPMs at 60MPH..

the motor could handle that..  it will burn more gasoline ...

what speed do you commute at on the highway or freeway...

55... 65.. 70... 75.... or foot to the floor..

is your clutch fan working properly... disengaging and engaging with variations in coolant temp in the radiator as the thermostat cycles. hot coolant for cooler..   if the fan clutch is seized.. it will restrict the RPMs of the engine and make a HUGE amount of noise..

fan clutches are better for cooling than flex fans..  so don't go crazy..

if you commute in 2 wheel drive.. and never use the 4 wheel drive commuting.. you might try out some Taller tires in the rear for commuting.. just as a trial...   this will replicate a gear change.. from 31 tall.. you might want to try something in the 34" tall range.. that should take your 3:73 gear down to just over 2200 at 60 MPH..

its just a trial...

you might want to price gear sets and calculate out the fuel savings verses the cost of dual gear ratio change outs..  

I do have a tach and my final drive is 1 to 1. My commute speed is usually 65 mph. I'm running a flex fan with an alluminum radiator and have no heating problems at all. I will try the taller tires and check my rpms while commuting. thanks