Re: Difference between 5HP30 & 5HP24 trans

["J. Cash" <j.cash@xxxxxxxxxxxx>]

Richard Vaughn asks:
What's the difference between 5HP30 & 5HP24 trans?

I have noticed several sites that list the transmission fluids for the
different model BMW/GM transmissions, show a 5HP30 (A5S 560Z) transmission
used in the earlier E38 (740 & 750) and a different model, 5HP24 (A5S 440Z)
for the '96 & later 740's. However the 750's still used the 5HP30 till the
end of that model E38 (2002). The specs show the earlier transmission
holding 13.1 litres, where the 5HP24 (4.4L) only holds 9 litres. Was the
5HP30 a 'heavier duty' transmission or what? Can anyone shed any light on
this for me?

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They are both ZF 5 speed automatic transmissions.

The 5HP30 is the ZF designation, and the A5S 560Z is the BMW designation for
the same unit.

The designation letters are defined as follows

ZF designation: 5(speeds); H(hydraulic control); P(planetary gear train); 24
(model)

BMW designation: A(automatic); 5(speeds); S(overdrive); 560(max torque in
NM); Z(ZF manufacturer).


I will use the BMW designations.

The A5S 560Z was essentially replaced by the A5S 440Z starting in early 96
and was introduced to all models on a gradual basis. The transition for the
5 series was in January 97. The E38 740 got the new transmission with the
move to engine change (M60 > M62). The exception, as you mention, was the
750 were the 560 transmission was retained to deal with the higher torque of
that engine.

The newer version (A5S 440Z) is a technically updated unit that was
developed mainly for weight and fuel saving.

The main differences between them are:
- - 440 is lighter by about 50 lbs. (complete redesign - I do not have the
internal details)
- - smaller unit of a slightly different shape.
- - 440 only has a primary oil pump (no flow with engine off) therefore towing
speeds must be restricted.
- - different electronics. The 440 can be "flash" updated while the 560 can
not.
- - use of different transmission fluid and capacity.

But the primary difference it the torque handling capacity. The new
"lighter" 440 unit can only handle 440nm compared to the older 560nm
capacity. This is not a problem however because the engine computer was
changed so that the engine torque output is reduced slightly during each
gear change. Thus the transmission never receives the full engine output
until the gear change is complete. Since gear changes cause the torque loads
to peak in the transmission this momentary reduction can save the need for
such a heavy transmission design.

Hope that helps.

Cheers
Jim Cash

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