Adapting the
Chevrolet & GM Standard Shift Bellhousings
to the
Jeep CJ & FSJ Borg-Warner T14, T15 & T18 Transmissions
Jeep CJ Transmission Versions
This adapter assembly adapts GM bellhousings to the CJ Jeeps with the T14 three-speed transmission, T15 three-speed transmission and the T18 four-speed transmission.
- The Jeep T14 was standard equipment on six-cylinder (AMC 232 & 258 c.i.d) engines from 1972 - 1975 and has an input shaft stickout length of 8.25" (measured from pilot tip of shaft to front face of transmission case).
- The Jeep T15 was standard equipment with the AMC V8 engines from 1972 - 1975 and has an input shaft stickout length of 8.25".
- The Jeep T18 was the optional transmission found in both I6 & V8 CJ Jeeps from 1972 - 1975 and has an input shaft stickout length of 9.1".
A pilot bushing is required, but not included due to the variables between Chevy and GM Gen. III+ engines. Go to this page to select the proper pilot bushing for this conversion . |
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Kaiser era Jeep CJ T14's from 1967 - 1971 (Buick V6) are not compatible with this kit.
For Jeep CJ T18's from 1976 - 1979, refer here.
Jeep FSJ Transmission Versions
This kit is also applicable to Full Size Jeeps ("FSJs", i.e.; Wagoneer, J-Truck, Cherokee), 1972 - 1979 with the T14, T15 and T18 transmissions.
- The Jeep T14 was standard equipment on six-cylinder (AMC 232 & 258 c.i.d) engines from 1972 - 1975.
- The Jeep T15 was standard equipment with the AMC V8 engines from 1972 - 1975.
- The Jeep T18 was the optional transmission found in both I6 & V8 FSJ Jeeps from 1972 - 1979.
The existing factory T18 cast iron front adapter plate (about 7/8" thick) will be used in conjunction with the new Novak adapter assembly. Jeep T18's using this adapter assembly will have an 8-1/4" transmission input shaft stickout length (measured from the pilot tip of the shaft to the front face of the T18's factory adapter plate).
Jeep T18's not fitting this description will require other versions of our adapter assemblies.
The Adapter
This plate style adapter is cast and machined of a high-grade aluminum alloy, featuring an integrated precision machined bearing retainer. Included are the GM bellhousing locator / throwout sleeve, seal and hardware.
Installation
The adapter is easily and quickly installed onto these transmissions and no change of input gear or other transmission internals are required. Cutting the transmission input shaft is not required as the adapter spaces the transmission properly for the GM crank and clutch assembly.
The total adapted length of a T14 is 11-7/16". The total adapted length of a T15 is 11-3/4".
GM Bellhousings
GM bellhousings typically feature either a 4-11/16" rear face bore or a
5-1/8" rear face bore, the latter typically only from Chevy / GM trucks from 1968-1991. Our adapter will work with both. If you are uncertain of your bellhousing bore, choose the 5-1/8" press-on spacer ring that can be used or omitted to cover either situation. The ring is easily returnable for credit if not used in the installer's application.
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| The classic Chevrolet bellhousing, with the four-bolt rear pattern. Buick, Olds, Pontiac and other bellhousings with the same rear face are equally compatible. | ||
If you're using a GM bellhousing that has a 5-1/8" bore, you will require the following sizing ring:
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Choosing Your Pilot Bushing
Your pilot bushing choice will depend on your particular GM engine. See our Pilot Bushings page to select this critical component for your conversion.
Flywheels
For GM engines prior to the Gen. III+ Series (LS & Vortec, 1997- present), you will use your GM / Chevrolet flywheel as per factory to your engine, which can be either the 153 tooth version or 168 tooth versions.
If you are using a GM Gen. III+ engine, we strongly recommend the use of our extended height LS / Vortec flywheel to normalize the clutch system. It features 168 teeth and is compatible only with 12" clutches.
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| This is the right and recommended GM Gen. III+ flywheel to use to standardize the clutch assembly, and acheive proper clutch geometry and release action. |
Clutch Assembly
This conversion uses readily available clutch components based on GM pressure plates and their geometries.
Whether you choose to use the smaller (10-1/2" to 11") or the larger (12") clutch assembly is your preference. Jeep CJ's are typically lighter vehicles and the smaller clutches are generally adequate and offer easy clutch pedal pressure. The larger clutches have more holding power and still have very reasonable pedal pressure when using the diaphram style pressure plate. A more detailed discussion on this topic is available here in Novak's Knowledge Base.
Pressure Plate
Use a standard GM style pressure plate that matches your particular flywheel, be it the 11" version for 153 tooth flywheels, or the 12" version for 168 tooth flywheels.If your existing Jeep disc (typically ~11") is in good condition, it can be used between the GM flywheel and pressure plate.
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Full Clutch Kit
For a full premium clutch assembly:
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Clutch Release System
Both factory mechanical and factory hydraulic clutch release systems can be made fully compatible with this conversion. A more involved discussion of this topic can be read here.
Mechanical Linkage
Installers using mechanical releases should use Novak's #RAGM release fork, which features the correct leverage ratio for a GM pressure plate in these 1970's Jeeps.
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Hydraulic Linkage
Individuals wishing to use their factory hydraulic master cylinder or who wish to upgrade to a hydraulic system can use Novak's #HCR hydraulic clutch retrofit assembly in conjunction with a master cylinder from a 1980-1986 Jeep CJ (7/8") or 1987-1990 Jeep YJ (3/4"). Custom firewall installation and clutch pedal modification may be required. Select your slave cylinder diameter to match.
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| Hydraulic clutch retrofits make for smooth, non-binding and easily adjustable clutch release systems. |
Throwout Bearing
The dwindling number of off-the-shelf release bearings and the bearings provided in the many full clutch kits on the market are, counterintuitively, not always the right length bearings for that particular pressure plate and can cause a clutch that will not fully release due to too short of a bearing, or a burned up bearing when they're too long and constantly riding the fingers.Novak's fully adjustable release bearing handily solves this concern, and is recommended for this conversion.
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| Novak's adjustable GM release bearing is the ultimate answer to setting up an optimal conversion or factory style clutch system. |
Engines & Engine Mounting
The Novak engine mounting system offers the best designs on the market for strength, ease and flexibility of installation. Whether you are installing a classic Small Block, a V6 or a Generation III powerplant, we've got you covered.
In any scenario, it is critical that the engine be installed (as the Jeep engines usually are) with an offset of 1" to 1-1/2" to the driver's side. Other engine mounts on the market - especially the bolt-in versions - do not take this into account and make other placement decisions for the installer that do not take the full powertrain into account. Novak offers what we have found to be the most intelligent engine mounting system for Jeeps available, allowing the installer to make an easy and satisfying decision as to powertrain placement with the new engine, T14, T15 or T18 transmission and Dana 20 transfer case all considered.
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| Novak's MM Series engine mounts, featuring excellent vibration dampening, superior strength and impressive adjustability - adjustable even after the engine is installed. The design and strength and affordability of our mounts are second to none. |
Engine Cooling
For your GM engine, we will suggest the use of our RadLock high-performance conversion radiators, which are rugged, easy to install and are extremely efficient in cooling in even the most demanding environments.
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| Our RadLock radiators offer a highly efficient and extremely durable cooling solution for your GM conversion engine. |
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 engine upgrade.
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| GM V8 engines, Generation I through Generation III+ are popular choices as are the Chevy V6s. The Buick V6 is also a good choice. |