Gear Ratios

Ideal Gear Ratio

When changing the tire size or the gear ratio in your Jeep, you want to ensure your ratio is within the correct power band for your use case. For highway driving, you want a taller gear ratio (lower number). This cuts down on your acceleration, but increases your MPG especially on highway driving since it keeps the RPMs lower. For off-roading, you want a shorter gear ratio (higher number). This provides quicker acceleration and more power to the ground for off-roading and rock crawling, but your top speed will be limited and you will get less MPG on the freeway. For daily driving, you want a balance between the two.

YELLOW = Highway Driving, Good Fuel Economy

GREEN = Daily Driver, Best Overall Performance

BLUE = Most Power and Towing, Reduced Fuel Economy

Idea Gear Ratio @ 65mph w/ manual transmission in 4th gear (1.00 transmission ratio). Automatic transmissions will have 15-30% higher RPMs due to slippage – Quadratec

Use the following calculators to see what your vehicle speed will be based on your axle ratio, tire height, transmission ratio, and engine rpm!

MPH Calculator


RPM Calculator

Engine Fluids

EngineFluid TypeCapacity
AMC 2.5L I4Above 0°F: 10W-30
Below 60°F: 5W-30
4.0 qts
AMC 4.0L I6Above 0°F: 10W-30
Below 32°F: 5W-30
6.0 qts
GM 2.5L I4Above 0°F: 10W-30
Below 0°F: 5W-30
3.0 qts
Renault 2.1Ltbdtbd
VM Motori 2.5Ltbdtbd

Transmission Fluids

TransmissionFluid TypeCapacity
Chrysler A904 3-Speed
Aisin-Warner AW-4 4-Speed
Chrysler 30RH 3-Speed
Borg-Warner T-4 4-Speed ATF Dexron II1.75qts
Aisin-Warner AX4 4-Speed75W-90 GL3 or GL4
10W-30 Motor Oil
2WD: 3.7qts
4WD: 3.5qts
Borg-Warner T-5 5-SpeedATF Dexron II1.75qts
Aisin-Warner AX5 5-Speed75W-90 GL3 or GL4
10W-30 Motor Oil
2WD: 3.7qts
4WD: 3.5qts
Peugeot BA-10/5 5-Speed
Aisin-Warner AX15 5-Speed75W-90 GL3 or GL4
10W-30 Motor Oil
2WD: 3.32qts
4WD: 3.27qts
New Venture Gear NV3550 5-SpeedMopar MT Fluid
SAE 30W Oil
3.3qts

Axle Fluids

AxleFluid TypeCapacity
Dana 3075W-90
75W-140 (towing)
1.26qts
Dana 3575W-90
75W-140 (towing)
1.75qts
Dana 4475W-90
75W-140 (towing)
2.00qts
Chrysler 8.2575W-90
75W-140 (towing)
2.11qts

Transfer Case Fluids

Transfer CaseFluid TypeCapacity
NP207
NP228/229
NP231
NP242

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4.0L

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