Adapting the Turbo Hydramatic 700R-4 & 4L60-E (early version) Transmissions
to the
Jeep Dana Models 18 & 20 Transfer Cases
Kit 178, adapting 700R4 & Early 4L60 transmissions (4wd style) to Jeep & IH Dana Spicer 18 transfer cases
Kit 172, adapting the 700R4 & Early 4L60 transmission (4wd version) to the Jeep & IH Dana Spicer Model 20
The Novak TH700R-4 / Early 4L60E to Jeep Dana 18 & 20 transfer case adapter is:
- Dana 18 version #178: 4.5" long for a combined transmission and adapter length of 27.9".
- Dana 20 version #172: 3.9" long for a combined transmission and adapter length of 27.2".
The adapters are machined of a 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.
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.
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
- Reluctor (if VSS version)
- Speed sensor (if VSS version)
On all kits, the installation notes show specifics on necessary cuts to the output shaft of your transmission necessary for installation
Our #172 / #178 adapter comes with a configurable mount foot. Attach a urethane rear mount like our #RMU, (see Related Products,below) for your crossmember. Do not hard mount this nor any powertrain component.
Applications & Compatibility
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
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.
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.
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. This superior, professionally built transmission, tested and ready to bolt in delivered to you is worth 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 operate it. If you are transplanting a complete GM engine/transmission package then the controller is likely there. If not, you will need to purchase a control module for proper operation.
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.
Compatible Jeeps
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.
Compatible Engines
Any engine that can be made to work with the TH350 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. Note: AMC engines sit back about 3" more than GM swapped counterparts. As such, this may limit the amount of lift avaialble in a short wheelbase Jeep.
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.
Related Products
Installation Requirements
Tools
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.
See Related Products above for pre-cut versions of these shafts.
Driveshafts
Driveshaft length changes may be required. Chevy engines (with their rear distributors) can install around 3" further forward than AMC engines. It is also recommended that LS family engines be installed 3" further forward than the factory block (using the back face of the block as the datum point) for exhaust clearance, firewall access, etc.
Because of the engine placement and transfer case SYE kits are frequently installed with many of these conversions, you may end up with a longer rear driveshaft (very desirable for lifted Jeeps) and a shorter front driveshaft.
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.
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.
Axles
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.
Placement
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 diameter front 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, featuring 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.
Also See
- Adapting AMC I6 & V8 Engines to the Chevrolet / GM Hydramatic Transmissions
- Complete TH350 Transmission Package
- Parts for the Dana Model 18 Transfer Case
- Parts for the Dana Model 20 Transfer Case
- Dana 20 Transfer Case Twin-Stick Shifter Kits
- The Novak Guide to the GM TH350 Automatic Transmission
- The Novak Guide to the Dana Spicer Model 18 Transfer Case
- The Novak Guide to the Dana Spicer Model 20 Transfer Case
