1991 Ford Mustang Axle Information & Ratios
Your Mustang will be equipped with a Vehicle certification label on the driver’s side door jam. This label will show your axle code under the “AX” slot.
All axles for these years are integral carrier type axles, however they will come in two sizes; a 7.5 inch and an 8.8 inch. There is a small metal tag bolted to the axle on the bottom line of the tag will be 3 pieces of information. The first piece will be the ratio, the second piece will tell you the ring gear size (7.5 or 8.8) and the last piece of information will be the build date (year, month & day).
Axle identification | Ratio and Type |
8 | 2.73 Axle Ratio – Conventional |
M | 2.73 Axle Ratio – Limited slip |
Y | 3.08 Axle Ratio – Conventional |
Z | 3.08 Axle Ratio – Limited slip |
F | 3.45 Axle Ratio – Conventional |
R | 3.45 Axle Ratio – Limited slip |
5 | 3.27 Axle Ratio – Conventional |
E | 3.27 Axle Ratio – Limited slip |
6 | 3.73 Axle Ratio – Conventional |
W | 3.73 Axle Ratio – Limited slip |
2 | 3.55 Axle Ratio – Conventional |
K | 3.55 Axle Ratio – Limited slip |
The following tabel contains torque specifications if repairing the axle
U bolt nuts to pinion flange | 8 – 15 lbs |
Differential pinion shaft lock bolt | 15 – 30 lbs |
Axle fille plug | 15 – 30 lbs |
Axle cover plate bolts | 10 – 15 lbs |
Anti-lock speed sensor | 40 – 60 inch lbs |
7.5 axle pinion shaft nut | 170 ft lbs |
8.8 axle pinion shaft nut | 140 ft lbs |
(4) rear of driveshaft bolts to axle companion flange | 71 – 95 ft lbs |
Upper axle arms to axle | 70 – 100 ft lbs |
upper axle arms to frame | 110 ft lbs |
lower coil spring axle arm to axle | 70 – 100 ft lbs |
Lower axle arm to frame | 80 – 100 ft lbs |
Upper shock absorber nuts | 14 – 26 ft lbs |