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Chrysler 4-speed automatics (42RE / 46RE)

The Grand Cherokee's overdrive TorqueFlites

The Grand Cherokee wanted something better suited to the road than the three-speeds, and that's where the RE family came in: four gears with overdrive and electronic control, derived from the old TorqueFlites. The 42RE (A500 base) backed the 4.0 straight-six; the beefier 46RE (A518 base) went behind the Magnum V8s.

42RE, 44RE and 46RE: one for each engine

The whole family adds a fourth overdrive gear (0.69) to the old three-speed TorqueFlite. The 42RE is the straight-six's; the 44RE a higher-torque variant; and the 46RE the one beefed up for the V8s' weight and grunt. They share the architecture but change the lower-gear ratios, because the V8 tolerates taller steps.

That same 42RE carried on in the WJ with the straight-six, while the 4.7 V8s moved to the more modern RFE transmissions.

RH vs. RE: hydraulic or electronic

The middle letter tells the control story. RH = hydraulic governor: the early Grand Cherokee ZJs (1993–95) ran the 42RH and 46RH, which decide shifts by oil pressure. RE = electronic control: from 1993–96 the box moved to commanding shifts with a solenoid and the computer, more precise and adaptable. The ratios don't change between RH and RE within each pair (42RH = 42RE; 46RH = 46RE): only who's in charge does.

In practice an electronic 46RE can drop into limp mode if a sensor fails, while the hydraulic 46RH is 'dumber' but also harder to confuse. Both are solid as long as you respect the fluid and cooling.

Specifications