Ford 2009 Mountaineer Owner's Manual page 803

The Vehicle Identification Number (VIN) contains the following
information:
1. World manufacturer identifier
2. Brake system / Gross Vehicle
Weight Rating (GVWR) / Restraint
System
3. Vehicle line, series, body type
4. Engine type
5. Check digit
6. Model year
7. Assembly plant
8. Production sequence number
TRANSMISSION CODE DESIGNATIONS
You can find a transmission code on
the Safety Compliance Certification
Label. The following table tells you
which transmission each code
represents.
Description
Five-speed automatic (5R55S)
Six-speed automatic (6R80)
2009 Mountaineer (mnt)
Owners Guide, 2nd Printing
USA (fus)
Maintenance and Specifications
Code
V
6
379