Ford A4LD / 4R44E / 4R55E

Ford's light rear-drive four-speed — in the Ranger and the first Explorers.

It is the 5R55E's predecessor and the two are constantly confused, because they appear in the same models in overlapping years and differ by one ratio. The parts do not interchange, and a listing that says only 4-speed automatic on a 1990s Ranger covers the whole family.

Its characteristic failure is the servo bore, exactly as on the five-speed that followed it: the aluminium case wears where the piston travels, pressure escapes past it, and the result is a delayed or missing 2–3 change and a slip that worsens as the transmission warms. Sleeving the bore is the standard repair and is far cheaper than replacement while the bands are intact.

The overdrive band and its servo are the other recurring item, producing a flare only in top gear at a steady speed — a slip that appears solely on the motorway is describing a band, not a tired gearbox.