Your 4.6is is fitted with the ZF 5HP24 transmission. 1st gear uses a sprag rather than a clutch for engagement when in ‘automatic’ mode, so a 2-1 rollout shift should feel completely seamless as the vehicle effectively freewheels in 1st, but the sprag is by-passed by the F brake in ‘manual’ mode. Can I ask if you are you operating the transmission in manual mode rather than in ‘D’ when you notice the issue?







The transmission uses an oil-to-water cooler so the fluid operates at around engine coolant temperature. 100°C is therefore normal. The overheat message will be displayed if the fluid temperature creeps much above 130°C and, before then, upshifts would be inhibited by the controller to keep the engine speed (and therefore the pump speed) high, to maximise flow through the cooler. Having said that, overheating fluid and too high a tickover speed, are the most common causes of a lumpy 2-1 downshift in ‘D’ (automatic mode).

Phil