Differential Housing Identification
Related Topics :
These Danas are
indistinguishable in appearance. The military Model 25 has a thick, cast
cover, while the 27 and civilian-model 25s have a thinner cover, will
accept taller gears, and backed V-6s.
The alloy-case Dana 28, with a 6
5/8-inch-diameter ring gear, came in Bronco IIs and Rangers with anything
but the 4.0-liter engine. Although 4.0-liter trucks come with Dana 35s,
most of the front suspension and/or drivetrain needs to be swapped to
replace a 28.
The Model 30, with a 7
1/8-inch-diameter ring gear, was the standard front differential in some
1972-75 CJ-5s and all 1975-and-later CJ-5s and CJ-7s. It is still used in
the front of Cherokees and Comanches, and will probably appear in the
front of the Grand Cherokee.
This axle, with a 7.56-inch ring
gear, is the frontend for 4.0-liter Ford Rangers and Explorers/Mazda
Navajos. The 35C version is found in the rear of Cherokees and
The 41, which has a ring gear size
similar to the Dana 44, came in early CJ-2As. The spiders are the same as
a 44's, but the carrier and gears aren't. It is almost universally swapped
out in favor of a Dana 44.
All domestic manufacturers have
used Dana axles, and the 44, with its 8 1/2-inch ring gear, is likely to
be a step up on anything smaller than a 1/2-ton. A narrowed 44 could be
the hot ticket for vehicles smaller than a full-size sport-utility. It was
standard under the front of pre-1976 Chevy Blazers and 1/2-tons, solid
front-axled F-150s and Broncos, and Jeep J-10/J-20s and Grand
The Ford-version Dana 44
Twin-Traction-Beam setup is similar to other 44s (ring gear diameters are
identical), but there are no axle tubes and the "cover" is actually the
suspension arm. It's standard in the front of any TTB-equipped Ford except
the F-250HD, which uses a Dana 50.
A Dana 60 looks deceptively
similar to a Dana 44, but the 60's 9 3/4-inch ring gear diameter is a
major factor in strength. It can be found in many 3/4-ton pickup and van
Almost identical in appearance to a
Dana 60, the Dana 70 is standard in heavy Dodge pickups and GM duallies.
The large 10.54-inch ring gear diameter will tolerate much torque, and is
suitable for diesel power and/or big tires.
Ford Rear Differentials
The small Ford rearend,
which sometimes uses a fiberglass cover, is found in Bronco IIs and
non-4.0-liter-powered Rangers. For bigger tires and/or engines, it's
usually swapped for a Ford 9-inch.
The 8.8-inch debuted in 1983 Broncos
and F-150s, and is now found also in 4.0-liter Rangers and
Explorers/Navajos. It is easily distinguished from a 9-inch by having a
cover on the back.
The venerable Ford 9-inch is
both readily available and strong. Later models have bigger axle tubes and
stronger housings. It was standard under 1966-88 F-150s and Broncos. It
also came on many vans and the Lincoln Versailles (a popular axle for
swapping because of the Lincoln version's disc brakes with parking
Ford's biggest axle comes
with semi-floating shafts in 1983-and-newer F-250s, and as a full-floater
in F-250HDs and F-350s. Applications are similar to the big GM 14-bolt and
the Dana 70.
GM Rear Differentials
GM CORPORATE 10-BOLT
The GM 10-bolt is
named for the number of bolts on the cover; ring gear diameter is 7 1/2
inches. Variations of this can be found in the rear of GM S-trucks and
some Isuzus, and in the front of S-trucks.
GM CORPORATE 10-BOLT
This 10-bolt, with a
larger 8 1/2-inch ring gear diameter, replaced the Dana 44 that was used
in the front of some pre-1977 GMs. It can also be found in the back of
1983-91 1/2-tons and in the front of 1983-87
GM CORPORATE 12-BOLT
The stronger 12-bolt,
with an 8 7/8-inch-diameter ring gear, can be found in various 1964-82 GM
1/2- and 3/4-ton front- and rearends.
GM CORPORATE 14-BOLT
The "small" GM
14-bolt has a 9 1/2-inch ring gear diameter. It was used in the rear of
1964-and-later GM pickups, and in the rear of 1984-91 3/4-ton
GM CORPORATE 14-BOLT
With a 10
1/2-inch-diameter ring gear, the biggest 14-bolt GM rearend looks much
like a Dana 70, and is but a few thousandths of an inch shorter in ring
gear diameter. This axle is commonly used with big engines and/or overly
large tires. It was used under 1973-87 3/4-tons.
Miscellaneous Rear Differentials
AMC MODEL 20
Used in 1976-and-later Jeep
CJs, the Model 20 rearend is both strong and weak. An 8 3/4-inch-diameter
ring gear provides strength; weaknesses are the housing itself and the
axle-to-hub retaining method. Converting to one-piece axles or
full-floaters gives this axle better stamina.
CHRYSLER 9 1/4-INCH
Mopar's 9 1/4-inch
rearend can put a stop (notice the octagonal stop sign cover shape) to
rearend woes on many lesser-equipped vehicles. Chrysler has used these
since 1969, on 1/2- and 3/4-tons.
Close to eight inches in ring gear
diameter, this rearend has been used on 1979-and-later 4Runners and
pickups. The four-cylinder turbo and 1988-and-later V-6 models have larger
side carriers and the same ring size in front.