1966 Ford Mustang Axle Information & Ratios
The first table is the code and gear ratio. If you know your axle tag number, simply go to the second table.
| Axle code | Ratio & type |
| 6 | 2.80 open differential |
| F | 2.80 locking differential |
| 2 | 2.83 open differential |
| B | 2.83 locking differential |
| 1 | 3.00 open differential |
| A | 3.00 locking differential |
| 3 | 3.20 open differential |
| C | 3.20 locking differential |
| 4 | 3.25 open differential |
| D | 3.25 locking differential |
| 5 | 3.50 open differential |
| E | 3.50 locking differential |
| 8 | 3.89 open differential |
| H | 3.89 locking differential |
| 9 | 4.11 open differential |
| I | 4.11 locking differential |
Years 1965 – 1968
| Year | Tag Code | Type | Ring Gear Diameter | Ratio :1 | Ring Teeth | Pinion Teeth |
| 1966 | WCZ-E | Conventional | 7.75 | 2.8 | 42 | 15 |
| 1966 | WDJ-B | Limited Slip | 7.75 | 2.8 | 42 | 15 |
| 1966 | WCX-F | Conventional | 8.0 | 3.00 | 39 | 13 |
| 1966 | WDJ-C | Limited Slip | 8.0 | 3.00 | 39 | 13 |
| 1966 | WCZ-S | Conventional | 8.75 | 3.50 | 35 | 10 |
| 1966 | WCZ-R | Conventional | 8.75 | 3.89 | 35 | 9 |
| 1966 | WDZ-A | Limited Slip | 7.75 | 2.80 | 42 | 15 |
| 1966 | WDW-C | Conventional | 8.0 | 3.25 | 39 | 12 |
| 1966 | WDW-E | Conventional | 7.75 | 2.80 | 42 | 15 |
| 1966 | WDW-A | Conventional | 7.75 | 2.80 | 42 | 15 |
| 1966 | WDW-D | Conventional | 8.00 | 3.50 | 35 | 10 |
| 1966 | WDZ-C | Limited Slip | 8.00 | 3.25 | 39 | 12 |
| Year | Tag Code | Type | Ring Gear Diameter | Ratio :1 | Ring Teeth | Pinion Teeth |
| 1966 | WDW-B | Conventional | 8 | 3.00 | 39 | 13 |
| 1966 | WDC-B | Limited Slip | 8 | 3.00 | 39 | 13 |
| 1966 | WDE-B | Conventional | 9 | 3.00 | 39 | 13 |
| 1966 | WEB-C | Conventional | 9 | 3.25 | 39 | 12 |
| 1966 | WED-C | Limited Slip | 9 | 3.00 | 39 | 13 |
| 1966 | WED-A | Limited Slip | 9 | 3.25 | 39 | 12 |
| 1966 | WDY-B | Conventional | 8 | 3.25 | 39 | 12 |
| 1966 | WDY-C | Conventional | 8 | 3.50 | 35 | 10 |
| 1966 | WEA-B | Limited Slip | 8 | 3.50 | 35 | 10 |
| 1966 | WDY-A | Conventional | 8 | 3.00 | 39 | 13 |
| 1966 | WEA-F | Limited Slip | 8 | 3.25 | 39 | 12 |
| 1966 | WEA-A | Limited Slip | 8 | 3.00 | 39 | 13 |
| 1966 | WEC-A | Conventional | 9 | 3.00 | 39 | 13 |
| 1966 | WEC-B | Conventional | 9 | 3.25 | 39 | 12 |
| 1966 | WEE-A | Limited Slip | 9 | 3.25 | 39 | 12 |
| 1966 | WEE-C | Limited Slip | 9 | 3.00 | 39 | 13 |
| 1966 | WCY-R | Conventional | 7.25 | 2.83 | 34 | 12 |
| 1966 | WCY-AA | Limited Slip | 7.25 | 2.83 | 34 | 12 |
| 1966 | WCY-E | Conventional | 7.25 | 3.20 | 32 | 10 |
| 1966 | WCY-AJ | Conventional | 7.25 | 3.20 | 32 | 10 |
| 1966 | WCY-L | Limited Slip | 7.25 | 3.20 | 32 | 10 |
|
Ratio |
Locking | 1966 |
|
2.80
|
6 | |
|
2.80
|
Yes | F |
|
2.83
|
2 | |
|
2.83
|
Yes | B |
|
3.00
|
1 | |
|
3.00
|
Yes | A |
|
3.20
|
3 | |
|
3.20
|
Yes | C |
|
3.25
|
4 | |
|
3.25
|
Yes | D |
|
3.50
|
5 | |
|
3.50
|
Yes | E |
|
3.89
|
8 | |
|
3.89
|
Yes | H |
|
4.11
|
9 | |
|
4.11
|
Yes | I |
