Adapting the Turbo Hydramatic 700R-4 & 4L60-E (early version) Transmissions

to the

Jeep Dana Models 18 & 20 Transfer Cases

Our TH700R-4 to Dana Models 18 & 20 conversion 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.

Product & Features



About the Adapter 

The Novak TH700R4/Early 4L60E 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".

Advanced computer modeling methods were integral to the design of our #107 adapter assembly.


The adapter itself is cast and machined of a high-grade aluminum alloy, featuring thick flanges, a heavy cross-section, and strength-adding gussets. The required spacer varies in length by application and is accommodated in the above dimensions. 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 18/20 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.

There are two versions of each kit to accommodate:

  • Standard, no suffix version for 700R4/4L60 - which is the conventional, hydraulically controlled (except for converter lock up) transmission built 1982-1992
  • E suffix version for Early 4L60-E - which is the electronically controlled version of the 4L60 built 1993 into ~ 2000. Please see notes below for further clarification.


The 107 Kit includes; adapter housing & necessary spacer, adapter shaft, bearings, seals, correct locator for your transfer case model bore, sensor with reluctor on “E” kits, hardware and instructions. These parts will come assembled to the extent possible. 

***Please read the full page before ordering. On “E” kits pay special attention to the version of your transmission. On all kits, the installation notes show specifics on necessary cuts to the output shaft of your transmission necessary for installation.***

Applications & Compatibility

Transmission Versions

All versions and years of the TH700R4 and 4L60E can be adapted to the Dana 18 & 20. The classic Chevrolet V8, 90 degree V6 pattern, and the less common 60 degree pattern used with the 2.8L in earlier Camaros, S-10 model trucks, 3.8L Buick, and in some later 90’s era Camaros will all accept the adapter. Either transmission version requires a 4x4 version output shaft be installed (if it is not already there) and cut to proper length. Those are available below and correct cut procedure with lengths needed are addressed in the instructions and noted below. 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. Many consider one of our complete Novak remanufactured and upgraded transmission packages. The advantage of a superior, professionally built transmission, tested and ready to bolt in delivered to you is definitely worthy of consideration.

4L60E Notes

The 4L60E transmission came in a multitude of versions over the years. Introduced in 1993 the original style version persisted through the late 90’s and possibly a little beyond in Van and full sized SUV applications prior to the body change in 2002. This kit will fit the one piece case, 4 bolt square pattern rear version of the transmission. If your transmission has a detachable bellhousing or a hexagonal 6 bolt rear pattern, see this kit for proper fitment.

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. 

Your Front Output Yoke

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 700R4/4L60E 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 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 Wagoneers, 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. Our 103 kits are best for these versions. 


Any engine that can be made to work with the TH700R4/4L60E will work with this adapter. All of the above mentioned native engines along with others that can be adapted via a front adapter such as our 437 series kits open up numerous possibilities.

Transfer Case Versions

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.

Transfer Case Input Gear

dana_18_20_input_gearOur 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.

Consult our informative Dana gears interchange chart if necessary.

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.

Related Products

700R and 4L60E 4x4 used output

If necessary, we offer a good, used version of the 4wd output shaft as produced or pre-cut to the proper length for adapter installation.



Novak’s adapter comes with a steel mounting bracket, compatible with our optional RMU urethane mount. As shown in the photo it is a strong and easy way to attach the rear mount. Hard mounting is not acceptable. If you don’t have other plans then this really is an essential part.


Dana 18 & 20 6 Spline Input Gears



Transmission Tunnel Cover

Because the transmission and transfer case shifters are often in a different location than factory in these Jeeps, this new transmission tunnel cover gives the installer a clean slate. There are no screw holes nor transmission & transfer case shifter holes, allowing the installer to drill and cut them as necessary. An easy way to get a perfect fit is to use the old cover as a template, making cuts as necessary, then overlay on the new aluminum piece for perfect holes.

The finish is natural brushed aluminum, which looks pretty terrific, but it can easily be primed and painted to suit, if desired.

This tunnel cover is compatible only with 1976-1986 CJ Jeeps.


D18 & D20 Rebuild and Gasket Options


Gasket and seals kit


Dana 20 Billet Pan and PTO Cover

These rigid and precisely machined billet bottom pans are a big step in getting your Dana transfer case sealed up. The thick, smooth-finished flange replaces the thin, warped factory pans and they virtually assure a drip-free seal. They also add structural rigidity to the overall transfer case. 


Transmission Cooling

Transmission Cooling is critical to the life of all automatic transmissions. Conventional in the radiator tank coolers are simply not adequate for long life on a Jeep’s transmission. Here are the products we recommend for best performance and ease of installation.



Installation Requirements


Tools required will vary depending on which kit is selected. The automatic transmission takes more specialized tools and knowledge, gaskets, seals, snap ring pliers, etc. The adapter requires typical mechanic's hand tools.

Transmission Output Shaft Length 

The 4x4 version output shaft needs modification as follows:

  • Dana 20 version: The installation of this adapter kit requires that the GM output shaft be cut shorter by 1-1/4 ". This should be done with a cut-off wheel and with care to prevent any debris from getting into your transmission, as discussed in the enclosed instructions. This step is required so that we can keep this adapter assembly as compact as possible.
  • Dana 18 version: The installation of this adapter kit requires that the GM output shaft be cut shorter by 5/8 ". This should be done with a cut-off wheel and with care to prevent any debris from getting into your transmission, as discussed in the enclosed instructions. This step is required so that we can keep this adapter assembly as compact as possible.


Transmission placement is largely determined by factory engine location. It is not necessary in typical conversions to change the engine position unless an engine is being swapped in at the same time as will often be the case with these kits. Setting the powertrain to the proper factory or conversion pitch angle - usually tilted down ~5 (3-7 acceptable) degrees - is recommended. Consult our engine conversion guides for more specific recommendations on placement if the engine is being replaced.

Clocking Information & Driveshaft / Yoke to Pan Clearance

Use of the factory size driveshaft and yoke is recommended. Our adapter design has maximized clearance between the transmission pan and yoke, but it is necessary that you install your GM engine offset 1-1/4" to the driver's side. If you are installing against a factory AMC engine with our 437-AMC adapter kit, your factory engine should already have this proper offset. 

Engines & Engine Mounting

If converting to a V8 in conjunction with this upgrade, aftermarket engine mounts are available to ease its installation. Because of the broad spectrum of engines and vehicle combinations used with this adapter, it would be difficult to list them all here. Whatever your application, Novak likely has the perfect solution. From a 225 Buick V6 in a CJ2A, to an LS3 in your JK, we’ve got you covered.


Novak's engine mounts, feature excellent vibration dampening, superior strength, and impressive adjustability - adjustable even after the engine is installed. The design, strength, and affordability of our mounts are second to none.

Engine placement in these applications is an effort in compromise to find the best position overall as a package. Generally the engine will be about 1” or even more towards the left, (driver’s side in the USA) away from the front differential in a CJ application. This gives the best balance of weight and more importantly clearance for the driveshaft going to the front axle. Your tight spots will be steering to exhaust on the left (hold that as tight as you can) and clearance for the front driveshaft on the right. Fore and aft position will vary with the Jeep model and engine. Have a CJ5 and Gen I with a rear distributor? You’ll be better off a little forward for more rear driveshaft length and clearance for that HEI. If you are in a longer Jeep and using an LS engine with no distributor, you’ll have more fan clearance and better balance if you hold it to the rear. Usually for ground clearance tuck things up nicely for height to avoid damage to oil pans and other life giving parts in the Jeep. Common sense and taking a step back to look at things overall goes a long way.


Driveshaft length changes are often required. Most conversions to these transmissions will require that the rear driveshaft be modified to be shorter and front driveshaft longer.

Some installers, concerned about the expense of new or modified driveshafts, attempt to let the existing driveshafts dictate engine, transmission and transfer case location, often to the detriment of the project. Our recommendation is to prioritize the correct position of drivetrain components over saving a few dollars which is usually regretted in the long run with compromised positioning.

Driveshaft modifications and rebalancing can be affordable when performed by driveline, RV or tractor implement specialists. New driveshafts are an option, but not necessarily a requirement in regards to the actual successful conversion if your existing driveshafts are in good condition.

Jeeps that require extensive travel or specialty-built driveshafts have this option available through several fabricators across the nation. These are normally specified after placement of the new transmission and measured at vehicle ride height. As the rear driveline gets shorter, it is often advantageous to us a Double Cardan or “CV style” rear shaft with the correct geometry at the axle to minimize vibrations and possible binding. 


Use of factory axles is completely acceptable with this conversion. Axle upgrades are not necessary, but they may be chosen for reasons external to this transmission upgrade.

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