Specifications

1997 AX15
transmission &
NP231 transfer
case.
AX15 (1989-99) - The overall transmission case length is 24.000”. The output shaft on this transmission is 23 spline and
protrudes approximately .400”. This transmission is normally found coupled to the AMC 4.0L 6 cylinder
engine. Transmissions from 1989-93 used an internal release bearing, while 1997-99 transmissions
were switched to the external slave cylinder. We have seen both internal & external
release bearings used between 1994-96; therefore we suggest that you verify what
you have. This transmission seems to be one of the better transmissions Jeep
used and is very capable of handling the horsepower and torque of a V8 engine.
The input shaft length of this transmission is 7-1/2". The input shaft spline is
an 1-1/8” 10 spline, which is the same as Chevy. The pilot tip diameter is .590”
on transmissions 1989-96, and .750” on transmissions 1997-99.
When converting to a Chevy engine and retaining either version of the AX15, our new GM conversion
bellhousing uses a new slave cylinder, P/N 716213, that is mounted externally.
When converting to a Ford engine, we manufacture an adapter plate that requires the use of a stock Ford bellhousing. Since the
AX15 has the hydraulic linkage, we recommend obtaining a 1987-88 F150 bellhousing. This bellhousing has provisions for a Ford
hydraulic slave cylinder. The adapter kit is supplied with a brass hydraulic fitting, enabling the Ford slave cylinder to have a standard
#3 male fitting for easy connection.
Chevy Engine to AX15 Ford Engine to AX15 Buick V6 Engine to AX15
712567 Bellhousing kit 712543 Adapter Plate 712567 Bellhousing kit
712567V Vortec V8Bellhousing kit 713006 Motor Mounts, or 713011 Motor Mounts
713001-S Motor Mounts, or 713130 Saddle mounts (1987-95)
713087 V8 Saddle Mount (1987-95)
713091 V8 Saddle Mount (TJs)
713092 Vortec motor mount (TJs)
713088 Vortec motor mount (YJs)
Optional Items:
CF360056 10-1/2” Pressure Plate CF260000 11” Pressure Plate CF360056 10-1/2” P.P.
383271 10-1/2” Clutch Disc CF360049 11” P.P. 383271 10-1/2” Clutch Disc
716213 Slave Cylinder 383735 11” Clutch Disc CF700010 Flywheel (231 V6)
N1430 Release Bearing 716130 YJ Hydraulic Fitting N1430 Release Bearing
716130 YJ Hydraulic Fitting 716130TJ TJ Hydraulic Fitting 716130 YJ Hydraulic Fitting
716130TJ TJ Hydraulic Fitting 716130H 42” Stainless Steel Hose 716130TJ TJ Hydraulic Fitting
716130H 42” Stainless Steel Hose 716130H 42” Stainless Steel Hose CF165552 11” Pressure Plate
383735 11” Clutch Disc
22-0001 Hi-torque starter 168T flywheel
22-0002 Hi-torque starter Vortec V8
(Headers and radiators are available for all of these applications)
NV3550 (2000-04) - This transmission was used in the TJ Wranglers equipped with the 4.0L 6 cylinder engine. This
transmission has a case length of 16.750”. The bellhousing indexes to this transmission with a dowel pin alignment. It has a 1-
1/8” 10 spline input shaft, and a pilot tip diameter of .750”. The output shaft of this transmission is a flush 23 spline. The bolt pattern
on the face of NV3550 looks almost identical to the AX15 transmission, except for a shift rail that protrudes from the top front of the
NV3550. The shifter handle location is 12” from the face of the transmission to the center of the shifter handle.
When converting to a Chevy engine, we offer a full bellhousing. Our GM bellhousing is designed for a 153 tooth flywheel; however,
most late model Chevy V6 & V8 engines only allow for a 168 tooth flywheel. In addition, the Generation III Vortec engines are only
equipped with a 168 tooth flywheel. These larger flywheels and clutches will fit our bellhousing as long as you use a hi-torque starter
without a nose cone. We offer two hi-torque starters for either the standard GM V6 and V8 and the Vortec V8s.
When converting to a Ford engine, we manufacture an adapter plate that requires the use of a stock Ford bellhousing. Since the
NV3550 has the hydraulic linkage, we recommend obtaining a 1987-88 F150 bellhousing. This bellhousing has provisions for a
Ford hydraulic slave cylinder. The adapter kit is supplied with a brass hydraulic fitting, enabling the Ford slave cylinder to have a
standard #3 male fitting for easy connection.
Chevy Engine to NV3550 Ford Engine to NV3550
712591 Bellhousing Kit 712544 Adapter Plate
712591V Vortec V8 Bellhousing Kit No motor Mounts for the Ford into the TJs
713091 Motor Mounts (V8 TJs)
713092 Motor Mounts (Vortec TJs)
105
identiftying the stock transmission (1987 & newer)