(pulled from celica-gts.com)
Toyota Differential Codes
The following is a table of Toyota differential codes. These codes are applicable to all Toyota models and years. You will find this code on the VIN plate in your car, typically on the firewall.
The code is comprised of four digits. The first digit is a letter that represents the ring gear diameter. The second and third digits are numbers that represent the differential ratio (Number of driveshaft rotations for each axel rotation). Lastly the fourth digit is also a number that represents the number of pinion gears and whether or not the unit is equipped with limited slip.
Examples
T382 = 6.7" Ring Gear @ 3.417:1 ratio, 2 pinions w/o LSD
F293 = 7.5" Ring Gear @ 4.10:1 ratio, 2 pinions w/ LSD
F303 = 7.5" Ring Gear @ 3.727:1 ratio, 2 pinions w/ LSD
Differential Codes
First Digit Second/Third Digit Fourth Digit
Ring Size R&P Ratio Pinions/LSD
A = 138mm
B = 145mm
C = 6.25"
D = 6.62"
E = 7.1"
F = 7.5"
G = 8"
H = 9"
J = 9.25"
K = 9.5"
L = 10.5"
M = 12.5"
N = 13.5"
P = 14"
R = 162mm
S = 6.38"
T = 6.7"
U = 6"
V = 10.6"
W = 15.5"
X = 142mm
Y = 158mm
01 = 3.30
02 = 3.36
03 = 3.545
04 = 3.556
05 = 3.70
06 = 3.889
07 = 3.90
08 = 4.111
09 = 4.222
10 = 4.375
11 = 4.444
12 = 4.625
13 = 4.79
14 = 4.875
15 = 5.125
16 = 5.286
17 = 5.60
18 = 5.714
19 = 5.833
20 = 6.167
21 = 6.667
22 = 6.78
23 = 6.833
24 = 7.64
25 = 4.556
26 = 5.571
27 = 3.364
28 = 4.30
29 = 4.10
30 = 3.727
31 = 3.909
32 = 6.591 or 5.583
33 = 7.503 or 5.583
34 = 6.781 or 4.786
35 = 7.636 or 5.60
36 = 4.778
37 = 3.583
38 = 3.417
2 = 2/no LSD
3 = 2/LSD
4 = 4/no LSD
5 = 4/LSD
