4L60E to Dana 18 and 20 Adapter

Our 4L60E (later version) to Dana Models 18 & 20 conversion makes for a tough and capable assembly both on-road and off-road. Because of the assembled length, this kit is only intended for longer wheelbase Jeeps, and other specialty conversions, such as Land Rovers, Land Cruisers, and other vehicles in which Jeep transfer cases would be useful.

These are strong transmissions, and Full Size Jeeps such as Wagoneer, J-Truck, etc. are conversion candidates for them. These are strong transmissions native to 1/2 ton truck, SUV and sports car applications. There are numerous upgrades available for the 4L60E should stock strength come into question.  The TH350 is the only real automatic option practical for CJ5 and other short wheelbase Jeeps.

The Novak 4L60-E to Jeep Dana transfer cases adapter is 6.5" long for a combined transmission and adapter length of 26.5" (equivalent to a 19.5" manual transmission).

The adapter is comprised of two main components. The transmission spacer is machined of aluminum alloy. The transfer case side is comprised of cast and machined high-grade aluminum alloy, featuring thick flanges, a heavy cross-section, and strength-adding gussets. The adapter shaft is machined from triple-alloy gear steel and provides superior strength as it is carried by two bearings unlike the other single bearing versions on the market. The Dana 18/20 input gear is rigidly supported by this configuration to handle gear side loads.

Kit contains:

• Adapter housing
• Transmission spacer
• Transfer case adapter shaft (choose your spline count)
• Bearings
• Seals
• Reluctor ring, clamp-on
• Vehicle Speed Sensor, GM version
• Transfer case to adapter gasket
• Transmission to adapter sealing ring
• Fastening hardware
• Modular steel mounting base
• Instructions

 

These parts will come assembled to the extent possible.

4L60-E Versions

This kit is for use with the 4wd version (short output shaft) version of the 4L60E. However, a 2wd version transmission can be used if a 4wd style shaft is installed. Once the 4wd shaft is installed, there are no inherent advantages to the 2wd vs. 4wd transmission. These kits are for the hexagonal, six-bolt tailhousing 4L60-E, typically made starting in 1996. Some 1999 and earlier versions have a four-bolt pattern tailhousing and non-removable bellhousing. See our 4L60 Early Kit if this describes your transmission.

The 4L60E is an electronically controlled transmission and requires a computer to control it. If you are transplanting a complete engine/transmission package then the controller is likely there. If not, you will need to purchase a control module for proper operation. We have two versions available below if you need one of those.

Compatible Transfer Cases

All Jeep models of the Dana Spicer 18 and Dana Spicer 20 transfer cases are compatible with this adapter assembly. IH versions of these transfer cases are also compatible. The correct input bore and spline count must be observed. This adapter is not suitable for the Ford Bronco transfer case as it is of an entirely different design in attachment and drop.

While it is mechanically possible to run the overdriven 700R4 / 4L60E assembly against a Dana 18 that features a Warn style overdrive, consider that you would have an overall overdrive ratio of .525 (.70 in the transmission and .75 at the transfer case overdrive). Transfer case output speed would be nearly double that of the engine speed. While this is a fascinating thing and excellent for mileage if the engine can sustain the low RPM cruise, the velocities that it could turn within your Dana 18 may be overwhelming. Keep in mind that the D18 and its overdrive were not designed for that type of RPM use. you would likely run into oiling issues at those sustained speeds.

Transfer Case Input Gear

Our adapter shaft is splined for six spline input gears.

• Six-spline gears (shown, right) are most common and usually found behind Jeep T84, T90, T86, T89, T98, T18, T15 & T150.
• The ten-spline version was only available on the 1966 - 1974 transfer cases against the Jeep T14 transmission
• Factory Jeep TH400 to Dana 20 combinations had a fifteen-spline input gear, which must be replaced by a compatible six spline version.
• International Harvester Dana 20's that had the TF-727 automatic had a 23-spline input gear, which must be replaced by a compatible six spline version.

 

All Warn and Saturn type overdrives are compatible with this conversion as long as the spline count is correct. We do not have replacement gears for the overdrive version.

Transfer Case Bore Size

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.

 

This is a great way to have a modern drivetrain, coupled with a strong cast-iron, gear driven transfer case!

 

 

• Fits All with 4L60E Transmission Conversion and Dana 18 or Dana 20
• Made in the USA