Rear
Axle Codes
Here is a table that gives the codes for different rear axle ratio,
differential type, manufacturer, and build date information. THe code is stamped on
the right axle tube (as viewed from the front of the car) on the forward side. It's
tough to see when it's still in the car. Of course some of the engine/tranny
combinations listed were not available on the 78-83 Malibu. But this will aid you in
finding a rearend to swap into your Malibu.
The first 3 digits indicate the axle code, the next one indicates
manufacturer (B=Buick, O=Olds, C=Chevy, P=Pontiac), the next is Julian date it was built
and the last it the shift it was made on. Limited slip rears had a tag on the differential
cover that stated it needs posi fluid... that's usually missing, if the cover has ever
been off. However, a "B" in the axle code (i.e., 2BX) usually indicates a posi.
The 7.5" rears have a differential cover that is smooth and
kind of a squared off oval shape. The 8.5" rears have a rounder shaped cover with a
raisedhorizontal area in the middle.
1978
Trans |
Engine |
Ratio |
Peg Leg |
Ltd Slip |
Std/Opt |
THM350 |
196 "C"
49 State |
2.73 |
2AB |
2BB |
STD |
THM350 |
231 "A" Cal
49 State |
2.73 |
2AB |
2BB |
STD |
THM350 |
231 "A"
49 State |
3.23 |
2AD |
2BD |
OPT |
THM350 |
231 "A"
49 State |
2.41 |
2AJ |
2BJ |
OPT |
THM350 |
231 "A"
Hi Altitude |
3.23 |
2AD |
2BD |
STD |
THM350 |
231 "G"
49 State |
2.73 |
2AB |
2BB |
STD |
THM350 |
231 "3"
49 State |
2.73 |
2AB |
2BB |
STD |
Gear
Ratio |
Ring
Gear |
Assembly Codes |
2.41 |
7.5" |
AZ, BZ |
2.56 |
7.5" |
RY, SY, RC, SC, AA, BA |
2.73 |
7.5" |
AX, BX, RS, SX, RD, SD, AB, BB |
2.93 |
7.5" |
AG, BG |
3.23 |
7.5" |
RU, SU, AU, BU, RG, SG |
1979
Trans |
Engine |
Ratio |
Peg Leg |
Ltd Slip |
Std/Opt |
THM350 |
3.8 (LD5) A |
2.41 |
2AJ |
2BJ |
STD |
THM350 |
3.8 (LD5) A |
2.73 |
2AB |
2BB |
OPT |
THM350 |
3.8 (LD5) A |
3.23 |
2AD |
2BD |
OPT |
THM350 |
3.8 (LD5)
High Alt |
3.23 |
2AD |
2BD |
STD |
THM350 |
3.8 (LD5) A |
2.73 |
2RX |
2BX |
STD |
THM350 |
3.8 (LD5) A |
3.23 |
2AU |
2BU |
OPT |
THM350 |
3.8 (LD5) A
Calif |
3.23 |
2AU |
2BU |
OPT |
THM350 |
3.8 (LC6) 2
Calif |
2.73 |
2AB |
2BB |
STD |
THM350 |
3.8 (LC6) 2
Calif |
2.73 |
2RX |
2BX |
STD |
THM350 |
3.8 (LC8) 3 |
2.41 |
2AJ |
2BJ |
STD |
THM350 |
3.8 (LC8) 3 |
2.73 |
2AB |
2BB |
OPT |
THM350 |
3.8 (LC8) 3 |
3.08 |
2AC |
--- |
OPT |
THM350 |
3.8 (LC8) 3 |
2.41 |
2AJ |
2BJ |
STD |
THM350 |
3.8 (LC8) 3 |
2.73 |
2AB |
2BB |
OPT |
THM350 |
3.8 (LC8) 3
Calif |
2.73 |
2AB |
2BB |
STD |
Gear
Ratio |
Ring
Gear |
Assembly Codes |
2.14 |
7.5" |
RH |
2.29 |
7.5" |
RA, AH, BH, AT, BT |
2.41 |
7.5" |
AJ, BJ, AZ, BZ |
2.56 |
7.5" |
RC, AA, BA, AY, BY |
2.73 |
7.5" |
AX, BX, RX, RD, AB, BB |
2.93 |
7.5" |
AG, BG |
3.08 |
7.5" |
AC, BC |
3.23 |
7.5" |
AD, BD, SC, RU, AU, BU, RG |
1980
Trans |
Engine |
Ratio |
Peg Leg |
Ltd Slip |
Std/Opt |
THM350 |
3.8 (LC8) 3 |
2.41 |
6RB |
6BJ |
STD |
THM350 |
3.8 (LC8) 3 |
2.73 |
6AB |
6BB |
OPT |
THM350 |
3.8 (LC8) 3 |
2.73 |
6RD |
6BB |
STD |
THM350 |
3.8 (LC8) 3 |
3.08 |
6AC |
--- |
OPT |
THM350 |
3.8 (LC8) 3 |
2.41 |
6RB |
6BJ |
STD |
THM350 |
3.8 (LC8) 3 |
2.73 |
6AB |
6BB |
OPT |
THM350 |
3.8 (LC8) 3
Calif |
2.73 |
6AB |
6BB |
STD |
Gear
Ratio |
Ring
Gear |
Assembly Codes |
2.29 |
7.5" |
AH, BH, AT, BT |
2.41 |
7.5" |
AJ, BJ, AZ, BZ |
2.56 |
7.5" |
AY, BY |
2.73 |
7.5" |
AX, BX, RX, AB, BB |
2.93 |
7.5" |
AG, BG, AW, BW |
3.08 |
7.5" |
AC, BC, AV |
3.23 |
7.5" |
AU, BU |
1981
Trans |
Engine |
Ratio |
Peg Leg |
Ltd Slip |
Std/Opt |
M64/Man 3 |
3.8 (LD5) |
3.08 |
8AC |
8BC |
STD |
MX2/350C |
3.8 (LD5) |
2.41 |
8AJ |
8BJ |
STD |
3.08 |
8AC |
8BC |
OPT |
3.23 |
8AD |
8BD |
OPT |
MX2/350C
M33/350 |
3.8 (LC8) |
2.73 |
8AB |
8BB |
STD |
3.08 |
8AC |
8BC |
OPT |
MV9/200C |
4.3 (LS5)
Diesel |
2.29 |
8AH |
8BH |
STD |
Gear
Ratio |
Ring
Gear |
Assembly Codes |
2.29 |
7.5" |
AH, AT, BH, BT |
2.41 |
7.5" |
BJ, AJ, BZ, AZ |
2.56 |
7.5" |
BY, AY |
2.73 |
7.5" |
AB, BB, AX, BX, RX |
2.93 |
7.5" |
AG, BG, AW, BW |
3.08 |
7.5" |
AC, AV, BC |
3.23 |
7.5" |
AU, BU |
1982
Trans |
Engine |
Ratio |
Peg Leg |
Ltd Slip |
Std/Opt |
MX2/350C
M31/250C |
3.8 (LD5) |
2.41 |
2AJ |
2BJ |
STD |
3.08 |
2AC |
2BC |
OPT |
3.23 |
2AD |
2BD |
OPT |
MX2/350C |
3.8 (LC8) |
3.08 |
2AC |
2BC |
STD |
MX2/350C |
4.1 (LC4) |
2.41 |
2AJ |
2BJ |
STD |
MV4/350C
MV2/350C |
5.7 (LF9) |
2.29 |
2AH |
2BH |
STD |
MV4/350C
MV2/350C |
4.3 (LT6)
Diesel |
2.41 |
2AJ |
2BJ |
STD |
2.56 |
2AA |
2BA |
Hi Alt STD |
Gear
Ratio |
Ring
Gear |
Assembly Codes |
2.41 |
7.5" |
BJ, AJ, BZ, AZ, BM, AM, CC, CQ, RZ,
CU, RB, CH |
2.56 |
7.5" |
BY, AY, CE, CN, CI, CV, BA, AA, RC,
CL, CY, RY, RD, CM, CZ |
2.73 |
7.5" |
AB, BL, AL, AX, BX, CW, CD, CR, BB,
RX, CJ |
2.93 |
7.5" |
AG, BG, AW, BW, RW |
3.08 |
7.5" |
AC, BC, AV, RF, RV, BV |
3.23 |
7.5" |
AD, BD, AU, BU, RG, RU, AE, BE |
1983
Trans |
Engine |
Ratio |
Peg Leg |
Ltd Slip |
Std/Opt |
MX2/350C
M31/250C |
3.8 (LD5) |
2.41 |
2AJ |
2BJ |
STD |
3.08 |
2AC |
2BC |
OPT |
3.23 |
2AD |
2BD |
OPT |
MX2/350C |
3.8 (LC8) |
3.08 |
2AC |
2BC |
STD |
MX2/350C |
4.1 (LC4) |
2.41 |
2AJ |
2BJ |
STD |
MV4/350C
MV2/350C |
5.7 (LF9) |
2.29 |
2AH |
2BH |
STD |
MV4/350C
MV2/350C |
4.3 (LT6)
Diesel |
2.41 |
2AJ |
2BJ |
STD |
2.56 |
2AA |
2BA |
Hi Alt STD |
Gear
Ratio |
Ring
Gear |
Assembly Codes |
2.41 |
7.5" |
RB, CC, AJ, AM, BM, CG, BJ, RZ, CH,
AZ, BZ, CU, CK, CX |
2.56 |
7.5" |
RC, CE, AA, CN, BA, CI, AY, CV, BY,
RY, CL, CY |
2.73 |
7.5" |
RD, CD, AB, AL, BL, CR, BB, RX, CJ,
AX, CW, BX, CM, CZ |
2.93 |
7.5" |
RE, AG, BG, RW, AW, BW |
3.08 |
7.5" |
RF, AC, BC, RV, AV, BV |
3.23 |
7.5" |
RG, AD, BD, RU, AU, BU |
3.42 |
7.5" |
AE, RK, BE |
3.73 |
7.5" |
AF, BF |
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