Here are some quick
facts about J Series Trucks. This is meant to be a general guide clearing up
some questions about the J Series through the years. This is not meant to be a
comprehensive list of all changes and models. For exact information about
drivetrain components by year, please see the
J Series Home site.
We like to break up the production years into 3 categories
-early,mid,and late.
The Early years 1962/3 to 1973
J Series Home site.
We like to break up the production years into 3 categories
-early,mid,and late.
The Early years 1962/3 to 1973
The early years were somewhat confusing in regard to model numbers.
There was the J100, 200, and 300 models and the J1000, 2000, 3000, and 4000s.
These numbers referred to the wheelbase of the truck and not the GVWR. Each of
the models could have more than one GVWR. For example, you could have a J2000
that was rated at 5000 or 6600 GVWR. Your individual serial number can give
clues as to what you actually have.
Under the hood, most sixes are AMC 232 or 258s with a few old 230 Tornados still grunting out torque with it's OHC. V8s could be the AMC-designed 327, Buick 350 or AMC 360.
If it's an auto tranny, most likely it is the GM TH400, with a few old Borg Warner boxes out there. Write us if you have the BW tranny!
Both auto and stick got the D20 xcase.
In the stick department, 4 speeds were the T98 or T18(A). There were a bunch-o-three on the tree boxes, but I'm going to go out on a limb here and say that most of them were T15s late in the early period, with T86/T89s more abundant near start up.
Axles were closed knuckle D44s up front, and D44 rear most of the time with some high GVWR early trucks getting the D53 or D70(!!).
Axles, springs, frame, bed, tailgate will not swap onto later trucks. Cab sheetmetal is the same as later trucks, however this may not necessarily mean that the cab will bolt to a later frame. Fenders, doors, and hood will swap. If you put an early cab on a mid or later frame we would like to hear from you.
Under the hood, most sixes are AMC 232 or 258s with a few old 230 Tornados still grunting out torque with it's OHC. V8s could be the AMC-designed 327, Buick 350 or AMC 360.
If it's an auto tranny, most likely it is the GM TH400, with a few old Borg Warner boxes out there. Write us if you have the BW tranny!
Both auto and stick got the D20 xcase.
In the stick department, 4 speeds were the T98 or T18(A). There were a bunch-o-three on the tree boxes, but I'm going to go out on a limb here and say that most of them were T15s late in the early period, with T86/T89s more abundant near start up.
Axles were closed knuckle D44s up front, and D44 rear most of the time with some high GVWR early trucks getting the D53 or D70(!!).
Axles, springs, frame, bed, tailgate will not swap onto later trucks. Cab sheetmetal is the same as later trucks, however this may not necessarily mean that the cab will bolt to a later frame. Fenders, doors, and hood will swap. If you put an early cab on a mid or later frame we would like to hear from you.
The Mid Years
These are by far our overall favorite trucks. Many improvements were
made in the beginning of the mid period. All of these trucks have disk brakes,
decent electrical (fuseboxes!), power steering, and AMCs best motors.
The 258 and the 360 are the most widely seen motors in the mid years.
Autos were TH400 and QT was mandatory with TH400.
Stick drivetrains are all still considered to be among the most beefy among hardcore 4 wheelers.
Model numbering system made more sense. J10- 1/2 ton with 2 GVWRs and J20-3/4 ton with 3 GVWRs.
Dana 44 front and rear unless J20, then Dana 60 rear.
Two wheelbases-7ft and 8ft bed options.
Great parts interchange between Wags, Cheros, and J trucks from here to the end.
Step side took a vacation during this period.
The 258 and the 360 are the most widely seen motors in the mid years.
Autos were TH400 and QT was mandatory with TH400.
Stick drivetrains are all still considered to be among the most beefy among hardcore 4 wheelers.
Model numbering system made more sense. J10- 1/2 ton with 2 GVWRs and J20-3/4 ton with 3 GVWRs.
Dana 44 front and rear unless J20, then Dana 60 rear.
Two wheelbases-7ft and 8ft bed options.
Great parts interchange between Wags, Cheros, and J trucks from here to the end.
Step side took a vacation during this period.
Late-Year Trucks 1980-1988
Switch to Chrysler TF727 tranny-another good box! No more QT or D20, NP208s and 229s took over xcase duties.
Cab loses distinctive brow over windshield.
Step side reappears during late period.
Dash changes in an attempt to modernize the aging design.
Ride height lowered to gain some precious MPG.
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