Adapting
AMC I6 & V8 Engines
to the
Jeep New Venture 3550 Transmission
This conversion kit joins the 2000-2004 Jeep NV3550 overdrive transmission to the popular 1976-1986 AMC Jeep bellhousings and their corresponding I6 & V8 bellhousings.
The adapter is precision designed and expertly CNC machined from alloy aluminum, providing ample thread engagement and powertrain structure. Precision indexing is achieved through locating dowels to the transmission and bearing retainer to the bellhousing. This adapter is 1" thick for a total adapted length of 17.7".
The adapter installs onto these transmissions with no change of input gear or other transmission internals. Cutting the transmission input shaft is not required as the adapter spaces the transmission properly for the AMC crank and clutch assembly. A new pilot bushing is required for this assembly. See Related Products below for the one matching your particular AMC engine.
Kit Contents
Included are the adapter plate, bearing retainer (which serves as a centering index for the GM bellhousing and clutch release bearing sleeve) and required fasteners.
Applications & Compatibility
The Jeep T150/T18 Bellhousing
The Jeep 4.0L bellhousing to AX15 & NV3550 transmissions
Bellhousing Compatibility
This adapter assembly is compatible with the following AMC bellhousings:
- T150 & T18 version (1976-1979)
- If you have this version, existing holes will be used and clearanced for new fasteners
- SR4, T4 & T5 version (1980-1986)
- If you have this version, it will be necessary to drill and clearance for new fasteners
- T176 version (1980-1986)
- If you have this version, existing holes will be used and clearanced for new fasteners
If you don't have one of the above bellhousings, but have the factory 1994-2004 4.0L to AX15 / NV3550 bellhousing (image, below), Novak recommends this installation method.
Compatible Jeeps
This conversion is compatible with CJ7 and longer Jeeps. CJ5 Jeeps do not have a long enough wheelbase for these longer, five-speed transmissions.
These are strong transmissions and Full Size Jeeps such as Wagoneers, J-Trucks, etc. are conversion candidates for them unless used for more aggressive driving or heavy work situations.
Compatible Engines
All AMC engines made from 1972-2006 are compatible with the above bellhousings and therefore this conversion, including the 232, 258 & 4.0L I6 as well as the 304, 360 & 401 V8's.
The 1980-1982 Jeep / GM Iron Duke 2.5L bellhousing is also compatible with this conversion; some ancillary pieces will vary a bit but the adapting process is the same.
Flywheel
The factory flywheels on all of the above engines are acceptable. Most will accept the recommended 10-1/2” clutch. There are instances of larger clutches in some trucks. If you have one of these applications the clutch diameter will need to match. The Iron Duke will also need the clutch matching its flywheel.
Clutch
The factory pressure plates, whether three-finger or diaphragm, are compatible with this adaptation. Ensure that the pressure plate is compatible with your engine, flywheel, bellhousing and actuation components. Use a 1980-1986 clutch disc as they have the required 1-1/8" x 10 spline configuration needed for the NV3550. 1976-1979 discs are typically 1-1/16" x 10 spline and not compatible.
The factory clutch release arms and their linkages can be retained and adapted as necessary. These AMC bellhousings can also be converted to hydraulic clutch release.
Transmission Versions
All versions of the NV3550 are compatible. However, the NV3550 will require a minor modification to their input bearing retainer, wherein the installer will trim the snout off near th base to allow clearance for the adapter and its new retainer.
Related Products
Installation Requirements
Tools
A drill, 29/64” bit, and various smaller bits are required, in addition to typical mechanic's hand tools.
NV3550 Installation Caveat
Note that NV3550 transmissions have a shift rail boss that protrudes through the adapter, and will require that the bellhousing be milled for clearance. The adapter can be used as a template to mark for this operation.
Placement
Setting the powertrain to the proper factory or conversion pitch angle - usually tilted down ~5 degrees (3-7 acceptable) is recommended.
Engines & Engine Mounting
Most of these conversions will occur where there is already and AMC engine in the bay. However, we do carry a universal style AMC V8 mount for other Jeeps in which this combination may be installed. See Novak's MMX Series engine mounts.
Driveshafts
Driveshaft length changes may be required.
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.