Specifications

TRANSMISSION-to- TRANFER CASE ADAPTERS
Photo courtesy of Kent Chipman AKA
“Mad Dog”, a satisfied Atlas owner.
Most of the transmissions listed below offer several adapter options. These adapters are all similar in length; however, the shaft
lengths and spline counts vary. Identifying what transmission your vehicle was originally equipped with will aid in obtaining the right
kit to maximize the spline engagement and avoid timely part exchanging.
Flush 23 kits fit transfer cases originally coupled to a NV3550, Torqueflite 999 & 904.
Long 23 kits fit transfer cases originally coupled to a AX15.
Flush 21 kits fit transfer cases originally coupled to a AX4, early AX5 and some AW4 transmissions.
Long 21 kits fit transfer cases originally coupled to a Peugeot, and 1997 & newer AX5.
TRUCK TRANSMISSIONS:
SM420 Truck 4SP: This transmission works great in Jeeps. The overall length is 10-1/2”. It has the lowest 1st gear available
of 7.05:1; 2nd 3.57:1; 3rd 1.7:1, and a 4th gear ratio of 1:1. This transmission was used in GM trucks from 1947 to 1968, and has
a 10 spline output shaft. As the years progress, it is getting harder to find this transmission and parts. The kit we offer is 5.25” long
and has a new spud shaft that couples to the New Process transfer case. This kit is supplied with the proper gaskets and bolting
hardware.
SM420 to New Process T/Cs Optional Items:
50-9702 Flush 23 spl. adapter kit 716008 Trans mount (or)
50-9704 Long 23 spl. adapter kit 716021 Trans mount (or)
50-9701 Flush 21 spl. adapter kit 716017 Trans mount
50-9703 Long 21 spl. adapter kit
SM465 Truck 4SP: Used from 1968 to 1988, this tranny replaced the SM420. It has an overall length of 12”. The 1st gear ratio
is 6.58:1; 2nd 3.58:1; 3rd 1.57:1, and 4th gear ratio of 1:1. This transmission was used in both the 2WD & 4WD vehicles. Throughout
its 20 years, the transmission case never changed; however, we have seen three different output shafts. The 1968-79 4WD
transmission used a 10 spline output shaft, which is easily adapted to. The 1968-88 2WD version used a 35 spline output shaft.
This transmission can also be used, but not without output shaft modifications. The 1980-88 4WD tranny used a long 32 spline
output shaft. We do not offer any adapters that couple to this output shaft because of its length. If you have this SM465 version, you
can change the output shaft to the 10 or 35 spline output. We offer adapter kits for both the 10 & 35 spline SM465 transmissions.
The adapters for these kits are 5.25” long and are supplied with the proper gaskets and bolting hardware. These kits use a spud
shaft to couple to the New Process transfer case. The kits for the 35 spline tranny requires the main output shaft to be shortened.
SM465 10 spline to New Process T/Cs Optional Items:
50-9808 Flush & long 23 spl. adapter kit 716008 Trans mount (or)
50-9801 Flush 21 spl. adapter kit (7” long adapter) 716021 Trans mount (or)
50-9809 Long 21 spl. adapter kit 716017 Trans mount
SM465 35 spline to New Process T/Cs
50-9812 Flush & long 23 spl. adapter kit
50-9811 Flush & long 21 spl. adapter kit
T18 Truck 4SP: This transmission, found in 1965 to 1985 Ford pickups, is identified by a case length of 11.875”. The 1st gear
ratio is 6.32:1; 2nd 3.09:1; 3rd 1.69:1, and a 1:1 4th gear ratio. The adapters we manufacture for this transmission come with a new
main shaft. This will usually allow the overall length of this transmission to remain ideal for most short wheel based vehicles. Ford
was not the only manufacturer who used the T18 transmission. When searching for a T18 in salvage yards, make sure the
bellhousing bolt pattern has a dimension of approximately 8-1/2” across the top, and 6-1/4” top-to-bottom. The input shaft stickout
should be approximately 6-1/2”. It is easier to adapt to the Ford T18 than to the Jeep or Scout T18. We do, however, also offer adapters
for the Jeep & Scout transmissions. These kits are all a main shaft style kit. The top end of the transmission must be rebuilt with
the new main shaft included in the kit. All of the adapters include a new 3.25” thick adapter plate that couples the transmission to
the New Process transfer case. The transmission bolt patterns between the Ford and Jeep transmission cases are different, so
we do offer two different kits for that reason. This transmission is also very popular for use as a transmission retrofit when retaining
the stock Jeep engine. For more information, see the 1987 & Newer Jeep Tranny Retrofit section of this manual.
Ford T18 to New Process T/Cs Optional Items:
50-7500 Flush 23 spl. adapter kit 716008 Trans mount (or)
50-7505 Long 23 spl. adapter kit 716021 Trans mount (or)
50-7501 Flush 21 spl. adapter kit 716017 Trans mount
50-7504 Long 21 spl. adapter kit
Jeep T18 to New Process T/Cs
50-7502 Flush 23 spl. adapter kit
98
transmission to t/c adapters (1987 & newer)