Adapting the

Turbo Hydramatic 700R-4 & Early 4L60-E Transmissions

to the

Jeep Models 207, 231, 242, 249 & 241OR Transfer Cases

Our TH700R4 / Early 4L60-E overdrive transmission to the Jeep New Process (or New Venture Gear) transfer cases conversion makes for a very strong, and capable assembly both on-road and off-road. It is one of the most persistently popular transmission swaps into Jeeps, providing a very compact geartrain, compatibility with excellent engines, and ease of installation.

Product & Features



The Adapter

The Novak TH700R4 to Jeep Model 300 transfer case adapter is very compact at only 1.1" long for a combined transmission and adapter length of 26.5". The adapter itself is machined from billet 6061 T6 aluminum, featuring thick flanges, a heavy cross-section, and superior strength.


Advanced computer modeling methods were integral to the design of our #171 adapter assembly. We were able to push the bounds of product and process well beyond the status quo.

Rear Mount Provision 

This transfer case adapter's design features a modular mounting and support system and mounting base, ready to accept our industry standard urethane isolator mount, available for purchase below.


Billet adapter housing, transmission output shaft, transfer case input shaft seal, transfer case to adapter gasket, transmission to adapter sealing ring, fastening hardware, steel mounting base, and instructions.

Applications & Compatibility


Any version and year of the TH700R-4 can be adapted using the 171 kit, including "90 degree" (Gen. I, II, III V6 & V8 Small Block or Big Block engines) and "60 degree" (early S10 Blazer 2.8L engine style) versions of the 700, as determined by your choice of engine.

Compatibility is for the 700R4 up through the early 4L60E with the four-bolt rear face.

700R4 Version

The 171 adapter is compatible with all versions of the TH700R4. If you have a 2wd TH700R4, a 4wd TH700R4 that is undergoing a rebuild anyway, are unsure what TH700R4 you have (or will have at the time of the conversion), or your D300 was just rebuilt (doesn’t leak) and you’d rather not open it back up, the 137-S kit is your best choice. The new 23 spline TH700R4 output shaft is machined from 300M alloy steel which provides a substantial strength upgrade. The new Novak shaft splines directly into the OEM style input shaft of a 300 transfer case. This requires disassembly of the transmission, and we recommend the services of a transmission professional.

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 Hydra-Matic. 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 Version Notes

These notes apply to the 171-E version of the kit which is otherwise the same as listed above. 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 standalone control module from one of various vendors for proper operation.


Strength Comparison of 27 vs 23 Spline Versions

The 27 and 23 spline shaft sizes are quite comparable in minor diameter (the diameter of the shaft at the root of the splines) and therefore, strength. Diameters are very close and the finer 27 spline vs the coarser 23 spline has shown no significant strength variation. The 300M material used in production of the Novak shaft is of a superior strength both in PSI yield and torsional resistance - which is exactly the type of load these shafts see. Aside from that, fundamental design strengths are comparable.

GM 27 spline and Jeep / Dodge 23 spline shafts have a history of great strength in factory applications and Jeep aftermarket set-ups.

Output Shaft Strength

broken_advance_adapters_shaftWe’re avoiding the problem of a broken shaft like this one by going through the trouble and expense of making our output shafts from a solid bar of exceptionally strong 300M alloy steel, instead of lower grade alloys or friction welding salvage GM shafts. A second, sometimes less obvious but pernicious problem is the issue of warpage during friction welding and heat treating - which cannot be corrected when the shaft journals are already ground and worn at or below factory specifications. Novak shafts receive a final grind of bearing journals after the heat treat process to ensure the ultimate finish. The Novak shaft is produced to factory specifications with stress risers removed. Our 4-axis CNC cut of spiral gear, oil feed passages and other features are no small tasks. This attention to detail, maximized strength through design and material along with precise tolerances provide the ultimate parts for your project.


This conversion is compatible with all longer wheelbase or stretched Jeeps. The TH350 is the only real automatic option practical for CJ5 and other short wheelbase Jeeps. 

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 TH700R4 should stock strength come into question. 


Any engine that can be made to work with the TH700R4 or early 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.

Related Products

Transmission Rear Mount

This transfer case adapter's design has a structural base for an industry standard urethane isolator mount, available for purchase. This is our preferred rear mount unit. Our kits are designed for it, and its usage is essential to protect powertrain components from the flex and movement typical of any automobile, but especially Jeeps.

Whether you are assembling onto a stock crossmember/skidplate or if you are setting up a high-clearance skid plate, you will find it to be a clean and simple process.



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.


New Process Transfer Case Shifter Options 

Often the shifters are linked to your old transmission, body, or both. As things move or even just to have a better setup these shifter solutions prove invaluable and extremely popular.


New Process Rebuild Kits 

The New Process (or later New Venture Gear) transfer cases are unusually strong for their mass and size. As long as your chain isn’t stretched and you keep up with fluid levels they will take a surprising amount of power and abuse. Like anything else, time and use takes its toll and these rebuild kits consist of the best available components including top quality chains and bearings. The rebuild process is not overly difficult, and if you are there anyway to put in an input gear, our advice is to rebuild, especially considering that the chains can stretch with use.

The 231 kits are divided early and late about 1993-1994. However there are no guarantees that things are original or that the change was made as a clean break 93 down and 94 up. If in question, the input bearing width on these models is a good indicator. Early uses a 24mm wide bearing and late is 16mm wide.


The Rubicon 241OR rebuild kit is available here.

The 242 kits are a little more pragmatic with chain use. Most of the light Jeep models are the same but there are some variations in those that used a V8 as well as the Liberty and AMG versions. These kits are offered as rebuild components and the chains separately. The same guidance applies to year breaks as the 231 for the rebuild kits. Chains are model and style specific.


Chains for the 242 had 2 pitch sizes, 2 joint styles and 2 widths and all in different combinations. 


Chain Style

Use the above illustration in the event you are not certain about the provenance of your NP242 transfer case chain joint type.

This is the most common chain used in the XJ and other light duty Jeeps.

The WJ Grand Cherokee and Dodge V8 applications commonly used this wider chain.

The Liberty is a unique animal with this version and rebuild kits vary as well.

Some Jeep XJ & ZJ (Europe), NP242ECE models used this chain.

The H1 AMG HMMWV, Humvee, Hummer version is 1-1/4” wide and the coarse pitch.

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.



23 Spline Input Gears

If you have a 21 spline input transfer case, our recommendation is to replace the input gear with a 23 spline version. The NP/NVG input gears are divided early and late about 1993-1994. However there are no guarantees that the transfer case is original or that the gear change was made as a clean break 93 down and 94 up. If in question, the input bearing width on these models is a good indicator. “E” Early uses a 24mm wide bearing and “L” late is 16mm wide. The photos show the differences in width of the bearing location and the stepped shoulder between the bearing and the gear. 23 spline input gears are available to replace the anemic 21 spline found in all too many applications. Please select the appropriate gear below.


Installation Requirements


Tools required will vary depending on which kit is selected. The automatic transmission shaft installation takes more specialized tools, knowledge, gaskets, seals, snap ring pliers, etc. We recommend the services of a professional to do this. Normal mechanics tools are required for the balance of the installation. The “E” kit requires drilling and tapping the transmission in the appropriate location per the instructions.


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. On a driver’s side drop transfer case, usually the later Jeeps, things often get a little easier as steering and front driveshaft are pushing you the same direction. 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. On later Jeeps with a Driver’s side drop transfer case and front differential, things are a little easier as the steering and offset are both pushing the drivetrain to the passenger’s side. Again, that 1 to 1-1/2” dimension is usually where you want to be. Common sense and taking a step back to look at things overall goes a long way.

Clocking Information & Driveshaft to Pan Clearance

Our adapter is drilled for multiple clocking locations and driver’s side drop transfer cases usually clear nicely in most all applications.

Engines & Engine Mounting

mmtj-g3If 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.


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.

Also See