maxum_101

Hello all
im looking at buying an unlimited with an automatic.... but would like to know what rpm you get at 100-110 km/h with a 3.21 rear gear
and also what rpm you get going at 100-110 km/h with a 3.73 gear

it will be a dd and will mostly be highway km.

any insight would be great

thanks

HilllClimb

with 3.73 you will run around 2300 RPM - 2400 RPM. (auto trans)
On highway I generally go 120 KM/H and it is at 2500 RPM

livdrty

with 3.73 MANUAL at 120km/H highway in 6th gear I'm doing about 1900-2000 rpm . . . just as a comparison.

JTPhoto JK

This total depends on tire size. Need more info..
i.e. A Sport with factory 29" tires on 16" wheels and 3.21 gears is gonna run about the same RPM as Sahara or Rubi with factory 32" tires on 17-18" wheels and 3.73 gears..
If you are considering at some point to go with 35" tires try and find one that has factory 4.10 gears.

To be clear, the V6s like to run a little higher rpm and get their best mileage at 2000-2200rpm. Lugging at 1500 -1800rpm will cost you.

snakeyes76

just as a comparison, i have a 2012 Rubi with 4.10s and 34" tires (true measurement) with an auto and I'm at 2000 rpm at 100km/h

JeepCACares

Your best bet would be to test drive the Jeep you're intending on buying or, if this is not possible, then trying to locate one at your nearest dealer might help you out.

Aside form the axle ratio, tire size (as it has been mentioned) will be your biggest factor. Make sure you know what tire size is on the vehicle.

Good Luck Jeep hunting!

Silver Billet

According to what I have read, the 3.73's will be the best $95 spent on a jeep. If you ever consider upgrading wheels/tires to off road it's money well spent and the 3.73's double the towing ability....

AutoJunkieMan

My jeep must be messed up then because I have a 2013 with the 3.6L manual with the 3.73 gearing and I drive at 100km/h nosing 2000rpm... :-S