Upgrade your Full Size Jeep’s drivetrain with this robust 700R4 to Dana 18/Dana 20 Transfer Case Adapter Kit. Engineered for strength and reliability on both road and trail, this adapter is ideal for longer wheelbase Full Size Jeep models—including Wagoneer, Grand Wagoneer, Cherokee, and J-Truck—as well as specialty conversions using Jeep transfer cases.

This kit is precision-cast and machined from high-grade 6061T6 aluminum, featuring thick flanges, a reinforced cross-section, and integrated strength-adding gussets. The included adapter shaft is crafted from premium triple-alloy gear steel and uses a two-bearing support design, offering exceptional durability and load handling—especially critical for the helical-cut input gears on Dana transfer cases.

Adapter Lengths:

• Dana 20 version: 3.9" (combined transmission/adapter: 27.2")
• Dana 18 version: 4.5" (combined transmission/adapter: 27.9")

Designed exclusively for non-electronically controlled 700R4 and early 4L60 (pre-1993) automatic transmissions, this kit is not compatible with 4L60-E electronic models. All Jeep Dana Spicer 18 and Dana 20 transfer cases are compatible, as well as most International Harvester versions (with correct input bore and spline count). Six-spline input gears are supported as standard.

Installation is straightforward, with most conversions completed in under two hours. Each kit includes a fully assembled adapter housing and spacer, adapter shaft, dual bearings, seals, locator for your transfer case model bore, all necessary hardware, and detailed instructions. Retain your original 1310 front output yoke—no need for special downsized yokes or additional modifications.

If you plan to use a 700R4 or early 4L60 with a Dana 18 transfer case and a Warn-style overdrive, be cautious. The combined overdrive ratio can significantly increase the transfer case output speed, pushing it well beyond what the Dana 18 was designed to handle. Prolonged use at these higher speeds can lead to lubrication problems and possible internal damage. This combination is not recommended for most builds.

Fits:

• All FSJs with 700R4 Transmission

Kit Contents:

• Adapter housing
• Adapter spacer
• Adapter shaft, 6 or 10 spline
• Bearings
• Seals
• Bearing adapter, 3-5/32" or 4"
• Steel mounting foot base
• Fasteners
• Instructions (will show specifics on necessary cuts to the output shaft of your transmission necessary for installation)

Important Notes:

• Transmission must have a 4x4 output shaft, trimmed to correct length per instructions.
• Warn and Saturn type overdrives are supported if the spline count matches.
• The diameter of the transfer case center input locating bore will be either 3-5/32" or 4". Most Dana 18's have a 3-5/32" bore, including those found against the T84, T90, T89 or T98. Some Dana 18's have a 4" bore, including those found against the T86 & T14 transmissions (Buick V6 engines), 1966-1971. All Dana 20's have a 4" bore, regardless of the transmission they were joined to.
• You will retain your factory 1310 yoke