Ford 2006 Mark LT Owner's Manual page 244

TRANSMISSION/TRANSAXLE CODE DESIGNATIONS
You can find a transmission/transaxle code on the vehicle certification
label. The following table tells you which transmission or transaxle each
code represents.
Code
B
2006 Mark LT (mlt)
Owners Guide (post-2002-fmt)
USA (fus)
Maintenance and Specifications
Description
Four-speed automatic (4R75E)
243