The 6-speed boxes have a single-piece casing, but the 5-speed is made up from four sections. The bellhousing, the oil pump housing, the main casing and the rear adaptor plate.
Clearly BMW & ZF thought it was worth the expense of developing a new version of the 5HP24 specifically for the 4.6l engine. The 280mm L51 torque converter will match the torque and power characteristics of the engine better. There must be some vulnerability in the D-brake, too, (engaged in 3rd & 5th gear) as they chose to increase its capacity by 25% for the 4.6l. I’m not sure why the B & E clutch valves were changed for the 4.6l but, again, car companies don’t go to the expense of doing stuff like that for no reason. I assume that the transmission controller is programmed differently for the 4.6l too.
I hadn’t heard any reports before of how the 4.4l version of the 5HP24 (1058 000 029) behaves in a 4.6l (1058 000 034) so I’m very interested to hear about your experience.
Phil
11-16-2023, 07:16 AM
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