Transfer Case Upgrades, Modifications, and Options

We get a lot of email from fellow Jeepers wanting to know what the options are for killer transfer cases. Some are looking for strength while others are looking for low gears. In this article we attempt to uncover all that is out there.

There are several modifications that can be performed on a Jeep transfer case. Most involve replacing the gears in the case to lower the gear ratio to improve slow trail performance. Many of these ratio changes can alter the gears in ranges of 3:1 up to 10:1. Many Jeepers also “clock” the transfer case. This involves rotating the case on the input shaft axis to allow for increased ground clearance under the Jeep’s mid section.

We will cover these on a basis of original Jeep transfer case model.

For more info on the “stock” versions of these transfer case see the Jeep Tech section under Technical and Info

Dana 300
Found in 1980 – 86 CJ

Whole Cases

Advance Adapters
Atlas II 2 Speed Transfer Case
Atlas 4sp 4 Speed Transfer Case

Case Gear and Shaft Upgrades

JB Conversions
4:1 LowMax gear set
Front Output Shaft
Rear Output Shaft

Tera Manufacturing
4:1 Tera Low

Advance Adapters
Rear Output Shaft

Rotation or “Clocking”

JB Conversions
Rotation Plate

Advance Adapters
Rotation Kit

Shifter Options

Advance Adapters
Twin Stick Shifter

 

Dana 20 and 18
Found in 1941 – 79 CJ

Whole Cases

None Commercially Available

Case Gear and Shaft Upgrades

Tera Manufacturing
3.15:1 Tera Low

Advance Adapters
3.15:1 Low Gears
32 Spline Output Shaft
Dana 20 and 18 Intermediate Gear Kit
Dana 18 Saturn Overdrive

Rotation

None Commercially Available

 

NP231
Found in 1987 – 2006 YJ and TJ Wranglers

Whole Cases

Advance Adapters
Atlas II 2 Speed Transfer Case
Atlas 4sp 4 Speed Transfer Case

JB Conversions
HD Case with Std SYE

Case Gear and Shaft Upgrades

JB Conversions
Slip Yoke Eliminator
Super Short Slip Yoke Eliminator
Wide Chain

Tera Manufacturing
4:1 Tera Low

Advance Adapters
Fixed Yoke Kit

Tom Woods
Tom Wood’s NP231 Super-Duty Tail Shaft Conversion Kit