If you had a dana 60, you'd have a powerlock, you have a 8.75, you have a suregrip. 2 types of sure grips used, cone and clutch. And no, a dana 60 powerlock will not fit in a 8.75, the gear diameter is much larger in the dana 60,
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I have found in many placesz an 8 3/4 clutch type rear from pre-1969 called a "sure grip powerlock":
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Information on Mopar 8 3/4 Rears
The Chrysler 8-3/4" rear axle assembly was introduced in 1957. It is a banjo-type, the differential is contained in a removable carrier assembly. The axle has an 8-3/4" diameter ring gear. There are three basic types available distinguished by their
drivepinion stem diameter. The 8-3/4" axle was the primary axle assembly used in most car lines through 1972.
8-3/4" Axle Center Section Types
The 8-3/4" axle was available in three basic types. The types are differentiated by the pinion stem diameter....1-3/8", 1-3/4", 1-7/8". The choice of axle pinion assembly was determined based on the application.
1-3/8" small stem pinion (741) Carrier casting numbers: 1820657 (1957-1964), 2070741 (1964-1972). These numbers are found on the left side of the carrier assembly.
This assembly was typically used in low weight/low horsepower (Small Block as an example) applications through low weight/medium horsepower and high weight / low horsepower applications. Pinion depth and bearing preload is set with shims. Differential bearing setting (i.e. backlash ) is set with threaded adjusters.
1-3/4" large stem pinion. (742) Carrier casting numbers: 1634985 (1957-1964), 2070742 (1961-1969). This assembly was replaced by a 1-7/8" pinion starting in the 1969 model year. 1970 Plymouth and Dodge b Bodies were the last models to use the 1-3/4" which appeared in a 2881489 case.
This assembly was typically used in high weight/medium horsepower applications through high weight/high horsepower applications. Pinion depth and bearing preload is set with shims. Differential bearing setting (i.e. backlash ) is set with threaded adjusters.
1-7/8" tapered stem pinion. (489) Carrier casting numbers: 2881488, 2881489 (1969-1974).
This assembly was introduced in 1969 and gradually replace the 1-3/4" unit through 1970 The 1-3/4" pinion also appeared in some 489 carriers during this period. By 1973, the 489 was the only unit available in passenger car applications.
This assembly was typically used in high weight/medium horsepower through high weight/high horsepower applications. Pinion depth is set with shims, preload is set with a crush sleeve. Differential bearing setting (backlash) is set with threaded adjusters.
All 8-3/4" carrier assemblies can be identified externally by the casting numbers. Additionally, the 741 commonly has a large X cast on the left side, the 742 may have a large 2 cast on the left side, and the 489 has a
large 9 cast on the left side. Through 1965, the factory ratio was stamped on the identification boss, followed by an S if
Sure Grip equipped. After 1965, a tag was affixed under one of the carrier mounting nuts to identify the ratio. If Sure Grip equipped, an additional Sure Grip lube tag was sometimes affixed; later years sometimes had the filler plug painted orange.
Gear ratios available on the 8-3/4" axle through the years include:
2.76, 2.93, 3.23, 3.31, 3.55, 3.73, 3.91, 4.10, 4.56, 4.89, 5.17, 5.57.
On OEM gear sets, the ratio is usually stamped on the edge of the ring gear. Ratio can be determined by the number of teeth on the ring gear divided by the number of teeth on the pinion gear or by counting the ratio of the number of turns of the pinion relative to one turn of the axle shaft.
The 8-3/4" center section is removed from the front of the housing. It is retained by 10 nuts on studs in the housing. The rear of the housing is smooth, the back is welded onto the
main housing.
The
axle tubes are part of the overall housing. To remove the center section, remove the wheels, brake drums, and drive shaft. Chrysler Cars made pre-1965 units have a pressed-on brake hub. Remove the axle shafts, 5 bolts on the backing plate flange on post 64 units, use puller for pressed-in pre-65 units.
Remove the 10 nuts on the housing studs around the carrier perimeter. Remove the carrier...may require prying, fluid will drain when carrier gasket seal is broken.<br>
Any 8-3/4" center section may be interchanged for another as an entire assembly.
Sure Grip
"Sure Grip" is the Chrysler name for a limited slip differential. It was optional on the 8-3/4" axles, 1958-1974.
Two styles were used.
1958-1969 used the Dana Power-Lock Pt# 2881487). This unit utilized clutches for the differential
locking action. The Power-Lock can be rebuilt using kit # 2070845 ( Mopar Performance PT # P4529484 ). In this assembly, axle drive shaft end thrust is taken by the thrust block assembly (replacement # 2881313). This Sure Grip appeared in the 741 and 742 assemblies. The axle bearings are: 25590 Timken cone, and 25520 cup, Chrysler numbers 1790523 and 696403).
The Dana Power-Lock can be recognized by its bolt-together assembly, bolts around the side opposite the ring gear, and multiple openings exposing the
cross shafts.
1969-1974 used the Borg Warner Spin Resistant (# 2881343). This unit utilized a spring-preloaded cone friction arrangement for the
locking action. Axle end thrust is taken by the cross shaft.
This Sure Grip appeared in 489 assemblies and 70 and later 741/742 assemblies.
8 3/4 Mopar Differental Rears
