D-18 / 20 / 300 T-case info

Dana/Spicer 18

Manufacturer: Dana-Spicer

Number of speeds: Two

High: 1:1

Low: 1.97:1 or 2.46:1

Case (or housing) material: Cast iron

Front output drive type: Gear (driver side drop)

Availability or aftermarket parts and support: High – Saturn overdrive, Novak Intermediate Shaft Kit, Tera Low 3.15:1 kit

Input spline count: 6 or 10

Rear yoke: Fixed (Jeep version had drum parking brake)

Planetary gear: No

PTO output: Yes

Available U-joint sizes for yokes: 1310

Output shaft spline count: 26

Shifter type: Mechanical

Weight: ~80 pounds

Length: ~8.5 inches (mount face-to-flange face)

Commonly found in: ’71-and-earlier Jeep, Willys vehicles, Ford GPW, IH Scouts

Dana 20

Manufacturer: Dana-Spicer

Number of speeds: Two

High: 1:1

Low: 2.03:1 or 2.34:1 or 2.46:1

Case (or housing) material: Cast iron

Front output drive type: Gear (driver side drop)

Availability or aftermarket parts and support: High – Tera Low 3.15:1 low-range, twin stick with old Dana 18 or aftermarket parts, 32-spline Advance Adapters rear output

Input spline count: 6 or 10

Rear yoke: Fixed

Planetary gear: No

PTO output: Yes

Available U-joint sizes for yokes: 1310

Output shaft spline count: 10 or 26

Shifter type: Mechanical

Weight: ~80 pounds

Length: ~10.5 inches (mount face-to-yoke center)

Commonly found in: ’72-to-’79 CJs, ’67-to-’73 Jeepsters, ’63-to-’70 Wagoneer/Gladiator/J-Trucks (and ’71-to-’79 with manual transmissions), ’66-to-’77 Ford Broncos, ’65-to-’79 IH Scouts (known as TC-145), some GM 1/2 ton trucks and Blazers/Jimmys

Dana 300

Manufacturer: Dana-Spicer

Number of speeds: Two

High: 1:1

Low: 2.62:1

Case (or housing) material: Cast iron

Front output drive type: Gear (driver side drop)

Availability or aftermarket parts and support: High – Twin stick setup, JB Conversions Lo-Max 4.0:1 low-range for the increase in strength where needed, and heavy-duty 32-spline front and rear outputs

Input spline count: 23

Rear yoke: Fixed

Planetary gear: No

Available U-joint sizes for yokes: 1310

Output shaft spline count: 26

Shifter type: Mechanical

Weight: ~86 pounds

Length: ~10.5 inches or 11.625 inches (mount face-to-yoke center)

Commonly found in: ’80-to-’86 Jeep CJs, 1980 IH Scout

 

Additional overdrive information

http://www.fourwheeler.com/how-to/transmission-drivetrain/154-0611-jeep-standards-capabilities-old-school/