According to this website;
You have an A4LD transmission whether it is a 2wd or a 4wd.
and what is funny is that tranny is so bad ford says it isn't a
ford tranny..mercury designed it and ford made the "mistake" of
using it for their trucks
There were three transmissions available in 1989. There was the
Mitsubishi unit that was often coupled with the 2.9 liter engine
and the Mazda M5OD (which is in my 1992 Ranger) for the manual
transmissions. Then, there was the A4LD automatic.