700R4 and 4L60 to Dana 18 / Dana 20 Adapter

This 700R-4 to Dana 18 / Dana 20 Adapter Kit makes for a very strong 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.

The Novak 700R4/Early 4L60 to Jeep Dana 18 & 20 transfer case adapter is:

• Dana 20 version: 3.9" long for a combined transmission and adapter length of 27.2".
• Dana 18 version: 4.5" long for a combined transmission and adapter length of 27.9".

 

The adapter itself is cast and machined of a high-grade aluminum alloy, featuring thick flanges, a heavy cross-section, and strength-adding gussets. It is machined from billet 6061T6 aluminum alloy. 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 / Dana 20 input is completely supported by this shaft and due to being helical cut is subject to side loading. The two-bearing design is much better equipped to handle these loads.

This kit WILL NOT FIT the 4L60-E that is electronically controlled.  It will ONLY fit the 700r4 and the early 4L60 that is Non-Electronically-Controlled (except for converter lock up), built from 1982-1992.

This kit includes the adapter housing & necessary spacer, adapter shaft, bearings, seals, correct locator for your transfer case model bore, hardware and instructions. These parts will come assembled to the extent possible.

All versions and years of the 700R4 and 4L60 from 1982-1992 can be adapted to the Dana 18 & 20. Either transmission version requires a 4x4 version output shaft be installed (if it is not already there) and cut to proper length. Correct cut procedure with lengths needed are addressed in the instructions. The basic installation is a 1.5-2 hour bench job and will include at least simple gasket and seal replacements. This is a good time for a more thorough master rebuild and update of the transmission.

With this Novak adapter, you will keep your existing 1310 front output yoke on your Dana transfer case. Because of the adapter design, a special downsized front yoke is not required.

While it is mechanically possible to run the overdriven 700R4/4L60 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 and sheer strength issues at those sustained speeds.

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 the Wagoneer, J-Trucks, etc. are conversion candidates for them. There are numerous upgrades available for the Transmission should stock strength come into question.

The TH350 is the only real automatic option practical for CJ5 and other short wheelbase Jeeps.

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.

Our adapter shaft is splined for six spline input gears.

• Six-spline gears 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 (Contact Us To Set Up A Custom Order)
• 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.

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.

 

 

• Fits All with 700R4 Transmission
• Made in the USA