ZF 5HP24A - Rear axle ratios – just the two?

[RRPhil]

Hi everyone. My first post on the forum – please be gentle

I have an interest in the ZF 5HP24 transmission and I have a fair amount of experience of its use in Jaguar, BMW and Range Rover applications but none, unfortunately, of the 5HP24A variant used in the Audis.

Clearly the 5HP24A is quite a bit different to the 5HP24, having the integrated front ‘axle’ and the Torsen differential unit in the transmission itself.



From what I can gather there are three different front 'axle' bevel gear sets used :

3.0909 (34/11)
2.9091 (32/11)
2.7273 (30/11)

as well as three alternative ratios for the front propshaft idler gear drive :

1.2069 (35/43/29)
1.1724 (34/43/29)
1.0000 (29/39/29)

and five alternative rear gearset ratios to drive the rear propshaft :

0.9063 (29/32)
0.8529 (29/34)
0.7838 (29/37)
0.7742 (24/31)
0.7368 (28/38)

All the potential combinations are actually reduced down to (just) five overall options, shown in the list below, which covers all 27 Audi variants of the transmission :



My question is, am I right in thinking that there are just the two rear axle ratios available i.e. 3.7000 (37/10) and 4.111 (37/9) for Audis fitted with the 5HP24A? If that is the case then drive to the front axle from the Torsen unit will always lead the rear slightly by between 0.04% and 0.46% depending on the model. Not that this is a large amount as, at worst, this speed difference is only equivalent to having 1.5mm less tread on the front tyres than the rears if the gearing at the front & rear was absolutely identical. I just wondered if any other rear axle ratios were offered by Audi with this transmission?

Phil