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Chrysler 8 3/4” Axle

Mopar has produced two types of rear axles in their history, Banjo and Carrier Tube.
Banjo axles have one-piece housing and a removable center section that contains the ring and pinion. This center section is bolted into the housing like a Ford 9" rear. This axle is the one and only 8 ¾ unit.
Carrier Tube axles have a center section which is an integral part of the unit with the axle tubes pressed or welded into it. Examples of this are the 7 ¼, 8 ¼, 9 ¼, 9 ¾ (Dana 60). 
7 ¼
Junk…read no more. Introduced in 1960; it was a low performance axle for /6 and small V8 cars. Casting numbers # 2070051, 3507881, 3723675
Info: 1 3/8" Pinion stem, 9 bolt cover, 55.6" width (flange to flange) / 53.2" housing flange to flange / 43.02" spring seat center to center.
SPECIAL NOTE: The 7 ¼ housing axle tubes are smaller in diameter than other units so the u-bolts and spring plates are useless if converting to a larger axle (i.e. 7 1/4 to 8 1/4, 8 3/4 or bigger).
8 ¼

Introduced in 1969. This rear end will be found in all Darts / Valients from 73 - 76 and also can be found in 340 Dusters and other A bodies. There is a sure -grip available beginning in 1973.Castings: 2852905, 3723598, 3723599
Info: 1 5/8 pinion, 57.6" wide, 10 bolt cover, 55.6" width (flange to flange) / 51.4 housing flange to flange / 43.02 spring seat center to center.
9 ¼

Introduced in 1973. It was designed to replace the expensive to produce 8 ¾ and by 1975 it replaced it totally for heavy-duty applications. Not offered in A - bodies.Castings: 3507890, 3507891, 3723199
Info: 12-bolt cover.
9 ¾ AKA Dana 60

Introduced in 1966. This rear end was not offered in A body cars except for the Hemi. The early rear ends were 23 tooth "Power Lok" (1966 - 1969) differentials. In 1970 the 9 ¾ went to 35 tooth axle shafts and were called "Track Lok" differentials. These particular ones will interchange with 8 ¾ axles, bearings and seals.
Info: 10-bolt cover

8 ¾
The only Banjo axle produced by Chrysler.Introduced 1957…DOA by 1974
Last year in A bodies: 1972 Last year in E bodies: 1974.  It is a banjo-type (Hotchkiss) axle,  the differential is contained in a removable carrier assembly which is extracted from the axle housing toward the front of the car.  It is retained by 10 nuts on studs in the housing.  The differential “cover” (although permanent) as viewed from the back of the car is smooth and hemispherical; it is welded onto the main housing.  The axle tubes are part of the overall housing.  The axle has an 8-3/4" diameter ring gear.  There are three basic types available distinguished by their drive pinion stem diameter.  The 8-3/4" axle was the primary axle assembly used in most Chrysler car lines through 1972.

Note: 8 3/4 above has Detroit locker differential (factory)

Where To Find One
A-body models include:
1964-76 Plymouth Valiant, 1964-69 Plymouth Barracuda, 1970-76 Plymouth Duster, 1972-76 Plymouth Scamp, 1964-76 Dodge Dart, 1971-72 Dodge Demon, 1973-76 Dodge Dart Sport, 1969-76 Dodge Dart Swinger
B-body models include:
1965-70 Plymouth Belvedere, 1965-74 Plymouth Satellite, 1968-74 Plymouth Road Runner, 1970 Plymouth Superbird, 1967-71 Plymouth GTX, 1965-74 Dodge Coronet, 1968-71 Dodge SuperBee, 1966-74 Dodge Charger, 1969 Dodge Charger Daytona
C-body models include:
All 1965-74 full-size Chrysler models (Newport, New Yorker, Imperial), 1965-74 full size Dodge and Plymouth models (Polara, Monaco, Fury, Sport Fury, etc.)
E-body models:
1970-1974 Plymouth Barracuda and 1970-1974 Dodge Challenger

Axles and Housings
Because the 8-3/4" axle was available in most body lines, there are a variety of housings available.  Following are SOME of the passenger car axle dimensions and notations.  The 'Perches' dimension is the distance center to center between the spring mount perches.  Dimensions are in inches.

  Body line      Track       Perches                Notes
-------------  ----------  -----------     -----------------------
A-body, 65-72    55.6         43.0         4" lug bolt circle,
                                           offered in heavy duty apps.
B-body, 62-70    59.2         44.0
B-body, 71-72    62.0         47.3
B-body, 71-72    63.4         47.3         station wagon
C-body, 64-72    63.4         47.3
D-body, 64-72    63.4         47.3
E-body, 70-74    60.7         46.0

A body Info: 55.6" width (flange to flange) / 51.4" housing flange to flange / 43.02" spring seat center to center

67 - 72 A body 43.02" 55.60"
62 - 70 B body 44.00" 5" 62.00"
71 - 74 B body Station Wagen 47.3" 63.4"

The 8-3/4 was also available in the 58-74 D100/W100 trucks (and variants), the 64-70 A-100 trucks and vans, the 67-70 A-108 trucks and vans, the 71-74 B100/B200 vans and non-listed 57-64 full and mid-size car models.

Notes:
1) The axle centerline to yoke/universal centerline is 12.35" for the 8-3/4" axle.
2) Any 8-3/4" center section may be interchanged for another as an entire assembly.
3) All 8-3/4" axle shafts, 65-74, are retained by a bolt-on flange.  Axles can be
   interchanged within housings of the same width.  The passenger side axle has a
   threaded adjuster to set axle shaft end play.
4) There was a slight dimensional change in axle shaft length when the Sure Grip design
    changed.  If interchanging axles with the slight difference, the threaded end play
    adjustment can be used to accomodate it.
 

Center Section Types
The 8-3/4" axle was available in 4 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.  Differential bearing setting (ie. backlash ) is set with threaded adjusters on all carriers.  All 8-3/4" carrier assemblies can be identified externally by the casting numbers.

657 1957 - 1964
741 1965 - 1974
742 1957 - 1968
489 1969 - 1974

1-3/8" small stem pinion   (aka. '657')
Carrier casting numbers:1820657 (1957-1964)
The 657 is as equally weak as the 741 described below but nowhere near as common. This was the year when Chrysler dropped the tapered axle shafts that had the brake assembly attached to the axle with a keyway and large nut. If you see this rear end....RUN!

1-3/8" small stem pinion  (aka. '741')
Carrier casting numbers:  2070741 (1964-1972).
The 741 is the weakest 8 ¾ center section you can buy. Commonly found in V8 A bodies before 1973. Besides being the weakest of the 8 ¾, has a limited amount of OEM and aftermarket bearings, gears, and other parts available. This unit when found in an A body rear is usually loaded with highway gears (Sure grips found in these rears can be swapped into other housings as long as you take the carrier bearing and races with you (as they are different). SG's themselves are all the same except for the clutch and cone type units.
Info: 1 3/8 Pinion
Pinion depth and bearing preload is set with shims.

1-3/4" large stem pinion (aka. '742')
Carrier casting numbers:  1634985 (1957-1964), 2070742 (~1961-1969).
This assembly was replaced by a phase-in of the 1-7/8" pinion starting in the 1969 model year.  1970 RW (Plymouth and Dodge mid-size) 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. A real good section with lots of bearing/gears/parts available. Biggest gear ratio available 5.57. It doesn't use a crush sleeve like the later 489 so a lot of racers prefer it. If you find one with an original sure grip it is almost 99% odds in favor it is a sweet clutch type.
Info: 1 ¾ Pinion
Pinion depth and bearing preload is set with shims.

1-7/8" tapered stem pinion (aka. '489')
Carrier casting numbers:  2881488, 2881489 (1969-1974).
This assembly was introduced in 1969 and was phased-in to relace the 1-3/4" unit through 1970.  Note:  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 applications through high weight/high horsepower applications. The strongest of the 8 ¾ units. As with the 742 there are tons of replacement parts available as well as gear ratios. Gear ratios available beyond 3.23 are: 3.55, 3.91, 4.10, 4.30, 4.57, 4.86, 5.13 and 5.38. Almost all original sure grips, except 1969, found in this housing are the non rebuildable and less desirable cone type.
Info: 1 7/8 Pinion
Pinion depth is set with shims, preload is set with a crush sleeve.

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.
Strength Considerations
Pinions
The 1-3/8" '741' pinion is the weakest.  It is still a capable unit in most moderate power, moderate traction street applications.  For high torque applications with high traction tires, the 1-3/4" or 1-7/8" should be considered.
The 1-7/8" '489' is supposedly the strongest.  Although the stem tapers down along it's length, it appears inherently stronger from a pinion stem perspective and the inherent strength of the fine splines (OEM gears).
The 1-3/4" '742' has a larger rear pinion bearing yielding greater strength in this area.  The 1-3/4" shares yoke mount diameter and mounting nut with the 1-3/8".
For perspective, the 7-1/4" has a 1-3/8" pinion, the 8-1/4 has a 1-5/8" pinion, the 9-1/4" (70s) has a 1-7/8" pinion.

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-Lok (# 2881487).  This unit utilized clutches for the differential locking action.  The Power-Lok can be rebuilt using kit # 2070845 ( Mopar Performance [MP] # P4529484 ). In this assembly, axle driveshaft 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 (Timken cup), (Chrysler numbers 1790523 and 696403).  The Dana Power-Lok 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.  The differential axle bearings are:  LM 104912 (Timken cone), and LM 104949 (Timken cup), (Chrysler numbers 2852729 and 2852728).  The Borg Warner Spin Resistant unit can be recognized by its lack of bolts on the side opposite the ring gear (like the Dana), and two openings exposing the preload springs.  Borg Warner sold this design to Auburn Gear who currently offers the replacement Sure Grip assemblies.

OPEN (NON - SUREGRIP) DIFFERENTIAL
Non-Sure Grip differentials can be identified by the large openings in the differential exposing the differential (aka. spider) gears. 
 There are no springs or clutches.

 
 A TYPICAL CONE TYPE DIFFERENTIAL
(NOTICE THE SPRINGS)

 

SURE GRIP (CLUTCH TYPE "POWER LOK") DIFFERENTIAL
 
SAME DIFFERENTIAL TAKEN APART

Interchange Notes:
The two Sure Grip types can be interchanged between the carriers if the matching differential axle bearings are retained.  The outside diameter of the cups are the same between the '741'/'742' and the '489'; the inner cone differs.  The Sure Grip differential can be used as a direct replacement for the non-Sure Grip within the carrier/bearing limits previously noted.

 

How do I know what size ujoint I have
 (1310, 1330 or 1350 series)?
The series is determined by two measurements, the end cap diameter and the width of the ujoint. First, measure the ujoint end cap diameter, if it is 1 1/16" or 1 1/8" then you have either a 1310 or 1330 series. Because each one of these two can have either cap diameter or a combination of the both on a ujoint, you must measure the width of the ujoint to determine which series it is. Measure the width with the caps on, if you come up with 3 7/32" (just under 3 1/4"), you have a 1310 series and if you get 3 5/8", you have a 1330 series.

If you measured an end cap diameter of 1 3/16", then you have a 1350 series ujoint and the width will ALWAYS be 3 5/8".


Universal Joint Yokes

The 8-3/4" axle was offered with two size cross & roller style universal joint.  These are referred to as the '7260' (2-1/8" yoke ID) and the '7290' (2-5/8" yoke ID).  Most Imperials and some C-bodies used a different univer- sal joint.  The '1330' type joint was used on Imperials and others with a constant velocity joint.  The '1330' uses outside snap rings instead of the inside snap rings used by the '7269' and '7290'.  The cap diameter for the '7260' is 1.078".  The cap diameter for the '7290' is 1.126".  The '1330' style joint cap diameter is 1.063".

There are four different yokes that have been used with the 8-3/4" axle for the '7260' and '7290' style universal joints.  The '741'/'742' assemblies used a coarse spline (10 splines) drive pinion.  Most of the aftermarket gears also use this coarse spline yoke mount.  There is a small yoke for the '7260' and a larger one for the '7290'.  The '489' assembly used a fine spline (29 splines) yoke.  Note: during the phase-in period of 69-71 for the '489' unit, there were several permutations of pinion size and yoke availability.  69-70 '489' units may be equipped with a coarse (10) spline pinion, particularly for the '7290'.  There are two yokes for the '7260' and '7290' universal joints with fine (29) splines.  Two additional yokes were used for the '1330' style universal joint in constant velocity applications, one for 10 splines and one for 29 splines.

Interchange Notes:
7260, 7290, 1330 yokes may be interchanged if the spline count is the same.
Note:  the 9-1/4" axle (73-up) uses the same fine spline yokes as the 8-3/4" fine spline units (29 splines).

Selected Parts Reference
Numbers listed for reference, some may be superceded or discontinued, some variances among models/years may occur.  Reference factory or replacement parts catalogs for exact replacement details.

Universal Joint Items
Item            Chrysler        Precision       Dana            TRW
(Detroit ref.)  (OEM or MP)     (Moog)          (Spicer)   (FederalMogul)
--------------  ------------    ---------       --------   --------------
 7260 joint      4364400         315G            5-1306X    20030, 20030P
 7290 joint      4057025         316             5-1309X    20059, 20059P
 Combination *     ---           347               ---      20226
 1330 joint      2533202         354             5-213X     20064, 20064P
 7260 strap kit  P4120468        318-10          2-70-38X   20704
 7290 strap kit  P4120469        492-10          2-70-28X   20705

* This is a combination of the 7260 and 7290 universal joints to allow
  mating of the two styles.

Yokes
3432485  -> 29 spline 7260 (2-1/8" ID), also P4529481
3432487  -> 29 spline 7290 (2-5/8" ID), also P4529483
3004872  -> 10 spline 7260 (2-1/8" ID), also P4529480
P4529482 -> 10 spline 7290 (2-5/8" ID), replaces 2808384, 3004873
2931813  -> 10 spline 1330, for constant velocity, ie. Imperial.
3432489  -> 29 spline 1330, for constant velocity, ie. Imperial.
1556556  -> pinion washer, concave, 3/16" thick, 13/16" hole diameter.
2070117  -> pinion washer, concave, 3/16" thick, 15/16" hole diameter.
1795175  -> pinion washer, flat, 3/32"thick, 13/16" hole diameter.
1795173  -> pinion nut, 3/4"-16 thread, 1-1/4" hex.
6027323  -> pinion nut, 3/4"-16 thread, 1-1/8" hex.
6028041  -> pinion nut, 7/8"-14 thread, 1-1/4" hex.

Sure Grip Items
Mopar Sure Grip axle additive - 4318060
Dana Power-Lock thrust block set - 2881313
Repair Kit, Dana Power-Lok - P4529484  (replaces 2070845)
Note: there is no repair kit for the Borg Warner/Auburn unit, but the internal cones have been remachined by others to successfully restore performance.

Shim Package
1-3/4" pinion -> P4452027
1-7/8" pinion -> P4452026

Ring Gear Bolts
P4529486 -> 71 and later  (also 4131255, pkg. of 10)
P5249163 -> 70 and earlier

Note:  the 71 and later bolts may be installed in the earlier units by drilling a shoulder relief in the attachment holes.

Gaskets, Seals
Position            Chrysler    National        C/R             Fel-Pro
---------------     --------    --------        --------        --------
Axle inner seal     4796698     8695S           15460             ---
Axle outer seal     2404216     8704S           19000             ---
Axle flange, foam   2070933     see flange kit  see flange kit   55032
Axle flange, shim   2881314     see flange kit  see flange kit    ---
Carrier gasket      1673367         ---            ---           RDS 65833
Pinion seal, 1-7/8  2931862     5126            18708             ---
Pinion seal, 1-3/4  2931862     7216            18912             ---
Pinion seal, 1-3/8  2931862     8515N           18708             ---
Yoke repair sleeve    ---       99187           99187             ---

Bearings
Position                 Cup/Cone, Timken, BCA           Notes:
-------------            ---------------------       ------------------
Differential, side       LM 104949/LM 104912          70-74, Borg Warner
Differential, side       25590/25520                  57-69, Dana
Pinion, front            M88048/M88010                1-7/8"
Pinion, front            HM89443/HM89410              1-3/4"
Pinion, front            M88048/M88010                1-3/8"
Pinion, rear             M804049/M804010              1-7/8"
Pinion, rear             M803149/M803110              1-3/4"
Pinion, rear             HM89446/HM89410              1-3/8"
Axle, outer              BCA A-7                      65-74
Axle, outer              C/R BR7                      65-74

Axle bearing service kit:  Chrysler # 3683966, one axle.
BCA differential kit: 1-7/8", # RA-301, 1-3/4", # RA-300.
BCA axle mounting flange repair kit: Left # A-7-LK, Right # A-7-RK.
C/R axle mounting flange repair kit: Left # A7-LK, Right # A7-RK.
Vent bolt - Chrysler # 4032798
Spring mounting pads (perches) - Chrysler # P4120074
'489' collapsible spacer (pinion bearing preload) - Chrysler # 2931687
Mopar gear lubricant - 4318058
Mopar wheel bearing lubricant - 4318064

Note:  the 8-3/4" axle shaft outer bearings require packing with grease as they are not  lubricated by the gear oil.

Appendix A:  8-3/4 A-body axle upgrade to 4.5" bolt circle

The 65-72 A-bodies were available with the 8-3/4" axle.  This was standard on all 340 equipped cars.  It was also included in heavy duty packages such as 318 with manual transmission and towing options.  It was often included in post 65 273 high performance manual applications.

The bolt circle (BC) on these vehicles was 4".  All other Chrysler vehicles (except some Imperials and trucks) of this era were equipped with a 4.5" BC.  It is commonly desired by A-body owners to change to the 4.5" BC when upgrading to later style disk brakes or to expand wheel choice.

A-body 8-3/4" axle shaft swap:
There are several methods to accomplish this.  Custom axles such as Strange, Summers, Moser, etc. can be specified with the larger lug pattern for the A-body housing.  Longer axles from a larger vehicle may be cut and resplined to fit the shorter A-body axle.  Donors for this operation are C-bodies, D-bodies, trucks and vans with the 8-3/4" axle and 4.5" BC.   When selecting a donor axle shaft, look for one that does not taper along its length.  Note: A-body 8-3/4" axles were equipped with 10x1-3/4" drum brakes.  Replace these with 10x2-1/2" or 11-2-1/2" brakes and associated hardware from the donor vehicle or similar.