1970 Differential ID Code
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Plant Codes:
G = Detroit Gear & Axle
B = Buffalo NY
W = Warren MI
Positraction Codes:
D = Dana posi diff
E = Eaton posi diff
W = Warren Motive
Decode - COZO522G
E
COZ = 3.73 Camaro Posi axle
05 = Month: May
22 = Day: 22nd day
G = Assembly Plant: Detroit Gear & Axle
E = Posi Source: Eaton
Posi or Non Posi
| Gear Ratio | Code |
| 2.56:1 | COA |
| 2.56:1 | COB |
| 2.73:1 | COC |
| Posi 2.73:1 | COD |
| 3.08:1 | COE |
| Posi 3.08:1 | COF |
| 3.36:1 | COG |
| Posi 3.36:1 | COH |
| Heavy Duty 3.08:1 | COI |
| Posi Heavy Duty 3.08:1 | COJ |
| Heavy Duty 3.36:1 | COK |
| Posi Heavy Duty 3.36:1 | COL |
| 2.56:1 | COM |
| Posi 2.56:1 | CON |
| 4.10:1 | COO |
| 2.73:1 | COP |
| Posi 2.73:1 | COR |
| 3.07:1 | COS |
| Posi 3.07:1 | COT |
| 3.31:1 | COU |
| Posi 3.31:1 | COV |
| 3.55:1 | COW |
| Posi 3.55:1 | COX |
| 3.73:1 | COY |
| Posi 3.73:1 | COZ |
| 3.07:1 | CRA |
| 3.31:1 | CRB |
| 3.55:1 | CRC |
| 3.73:1 | CRD |
| 4.10:1 | CRE |
| 2.56:1 | CRF |
| Posi 2.56:1 | CRU |
| Heavy Duty 3.08:1 | CRH |
| Posi Heavy Duty 3.08:1 | CRI |
| 2.73:1 | CRX |
| Posi 2.73:1 | CRY |
Positraction Casting Numbers
| Axle | Casting Number | Series | Gearing |
| 12-bolt Passenger | ED 32088 | 2 | 2.73:1 and down |
| 30140PM1 | 3 | 3.08:1 to 3.73:1 | |
| EDB 30174 | 4 | 3.90:1 and up | |
| Corvette | ED 32297 PW 3 | 3 | 2.73:1 to 3.70:1 |
| EDB 32298 | 4 | 3.90:1 and up | |
| 8.5 corporate | 410408N | 3 | 2.73:1 and up |
| 410409N | 2 | 2.56:1 and down | |
| 8.2 10-bolt | ED 21118 | 2 | 2.73:1 and down |
| EDB 30116 | 3 | 3.08:1 and up |
Rear Axle Gear Ratios
The gear tooth ratio of the ring and pinion for example
10-41 is stamped on the pinion head or stem and
also on the ring gear. Therefore you can calculate the axle ratio.
Ring gear tooth count=41
Pinion tooth count=10
41/10 = 4.10
| Tooth Combinations | Ratio |
| 16-41 | 2.56:1 |
| 15-41 | 2.73:1 |
| 14-43 | 3.07:1 |
| 13-40 | 3.08:1 |
| 13-43 | 3.31:1 |
| 12-37 | 3.08:1 |
| 12-41 | 3.42:1 |
| 11-37 | 3.36:1 |
| 11-39 | 3.55:1 |
| 11-41 | 3.73:1 |
| 10-41 | 4.10:1 |
| 9-37 | 4.11:1 |
Rear Ends
| 1970 | 1970 | 1971-75 | |
| 10-Bolt | 12=Bolt | 10-Bolt | |
| Bolt Diameter (in.) | 3/8 | 3/8 | 7/16 |
| Ring Gear Diameter (in.) | 8.20 | 8.875 | 8.50 |
| Pinion Diameter | 1.438 | 1.625 | 1.625 |
| Axle Splines | 28 | 30 | 28 |
| Overall Dimensions: | |||
| Axle tube flange to axle tube flange | 55 1/4 | 55 1/4 | 55 1/4 |
| Between centerlines of spring seats | 45 3/8 | 45 3/8 | 45 3/8 |
| Axle shaft length | 30 5/32 | 30 5/32 | 30 5/32 |
Remember if you have a posi unit to add 2 bottles of limited slip lubricant.
