Chrysler Ultradrive (41TE / 62TE)

Chrysler's electronically controlled four-speed automatic — the transverse Ultradrive / A604 / 41TE and its longitudinal cousin the 42RLE — in the Neon, Stratus, Sebring, PT Cruiser, Voyager, Grand Caravan, Journey, Liberty and the TJ and JK Wrangler.

Its reputation is among the worst of any automatic, and the reason is a fluid. These units require ATF+4 — a Chrysler specification, not a Dexron or Mercon equivalent — and they were filled with the wrong fluid on an industrial scale in their early years, by owners, by quick-fit shops and by dealers who did not yet stock it. The wrong fluid produces exactly the symptoms the transmission became notorious for: shudder on the 2–3 change, then slipping, then failure.

So the single most useful question about any of these is what fluid is in it, and the answer is very often unknowable — which is why a fluid and filter service with the correct specification is the first thing to do on an unknown example rather than the last.

Beyond fluid, the solenoid pack and the input and output speed sensors account for most electrical faults, and both produce a limp mode locked in second that reads as catastrophic and is not. A unit that has had ATF+4 all its life is a great deal better than the reputation suggests.