Ford 2006 Mountaineer Owner's Manual page 320

Maintenance and Specifications
TRANSMISSION/TRANSAXLE CODE DESIGNATIONS
You can find a
transmission/transaxle code on the
Safety Compliance Certification
Label. The following table tells you
which transmission or transaxle
each code represents.
Description
Five-speed automatic (5R55S)
Six-speed automatic (6R60)
320
2006 Mountaineer (mnt)
Owners Guide (post-2002-fmt)
USA (fus)
Code
V
X