Specifications
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jeep tranny retrofits (1941-79)
1941-79 JEEP TRANNY RETROFITS
(JEEPS RETAINING STOCK AMC ENGINE & STOCK TRANSFER CASE)
On many of the late model Jeeps, the stock engines that were used were adequate for horsepower and torque. An example of these
engines include the 4.0L, 4.2L, 258 6 cyl., 304, 360, and 401. The weak link is normally the stock transmission up against these
power plants. We also have many customers who wish to retain their 4 cylinder, but change their transmission for better gearing.
We manufacture bellhousing adapters to retain these stock AMC-Jeep engines with a new, stronger and, in most cases, a lower
geared transmission. The part numbers listed below are just the bellhousing & transfer case components required. A crossmember
support & clutch components may also be necessary.
FORD T18 & NP435: These transmissions are popular to retrofit into these vehicles. They are a heavy-duty 4 speed with a
granny low 1st gear. When converting to the AMC blocks, a stock AMC bellhousing can be used (Jeep P/N 8133951, 3236291 or
AA P/N 712599). These bellhousings are normally found coupled to T150 & T176 trannys in Jeeps 1976-1983.
P/N 716156 - AMC pilot bushing (required for all applications)
P/N 384180 - AMC Clutch disc (required when the stock tranny has 1-1/16” 10 spline)
P/N 712599 - AMC stock T150 and T176 bellhousing (for early Jeep engines)
P/N 712569 - AMC 4.0L to Ford truck transmission (T18 & NP435)
Ford T18 T/C Adapters Ford NP435 T/C Adapters
50-7201 Large Hole Dana 18/20 adapter 50-6102 Dana 18/20 adapter
50-7202 Small Hole Dana 18 adapter 50-3801 Dana 300 & NP flush 23 spline
(A crossmember support will be necessary on these conversions)
SM420 & SM465: GM truck 4 speeds with a granny low 1st gear. Ideal for rock-crawling. The two bellhousings below bolt to
the stock Jeep engines and allow the GM truck 4 speeds to be coupled into the Jeep drivetrain. These bellhousings have the flywheel
sensor option necessary for the 4.0L blocks. They also work fine for any other earlier Jeep engine.
P/N 712570 - AMC engines to SM420 (4.686” bellhousing index)
P/N 712571 - AMC engines to SM465 (5.125” bellhousing index)
SM420 T/C Adapters 4WD SM465 T/C Adapters
50-2401 6 spline Dana 18/20 adapter 50-4703 6 spline Dana 18/20 adapter
50-2402 10 spline Dana 18 adapter 50-4702 6 spline Dana 18/20 adapter
50-4701 10 spline Dana 18 adapter
(For 2WD SM465 adapters, see the Transfer Case Selection Chart)
(Crossmember support & clutch components will be necessary on these conversions)
NV4500: GM & Dodge truck 5 speeds with a 5.61 first gear ratio and 27% overdrive. This transmission is one of the most popular
options when it comes to a transmission retrofit.
The most popular and the shortest way to convert the NV4500 into the Jeeps is using one of our full bellhousings. Part No. 712571
bellhousing is designed mainly for the 1995 & earlier GM NV4500 transmission. Part No. 712568 can be used on both the 1996
& later GM transmissions. The stock Jeep flywheel thickness must be 1-1/8” or thinner to obtain proper clutch clearance. Thicker
flywheels are sometimes found on some early Jeep V8s.
P/N 712571 - AMC engines to GM NV4500 (up to 1995)
P/N 712568 - AMC engines to GM or Dodge NV4500 (1996 & up)
P/N 50-0210 - GM NV4500 to Dana 18/20
NV3550 into a CJ5: Although this is a fairly long transmission to fit into these short wheel-base vehicles, it can be accom-
plished when used with a GM V6 engine swap. The GM V6 is short enough to be set further forward in the frame rails and then
coupled to the NV3550. The overall length of the 5 speed with the bellhousing and the transfer case adapter is 24.875” long. This
ideal engine and transmission combination provides the needed highway gearing for these Jeeps and still provides a usable low
gear for off-roading. The front driveshaft has good clearance on the transmission; however, count on lengthening and shortening
the driveshafts to fit the new drivetrain length. Other modifications would include transmission crossmember support and
floorboard modifications for the shift handle. NOTE: The GM 4.3 V6 should be a 1996 & earlier model because of the flywheel
limitations on the later model blocks and oil pan configurations.
We do not offer this as a complete kit. The following parts will be required for this CJ5 installation:
P/N 26-3550 - NV3550 transmission
P/N 712591 - Bellhousing to mate the NV3550 to the GM 4.3 V6 (153 tooth flywheel limitation)
P/N 50-8602 - Transfer case adapter NV3550 to Jeep Dana 20 transfer case