From MYs 89 to 91, S4s worldwide were fitted with the A28/16 auto
transmission, according to the workshop manual. This has a 13:33 (2.538:1) final
drive ratio.
To check whether a different transmission type may have been fitted as an
option, you can confirm the type by the transmission number. According to the
WSM, "from model '88, the gear box number will be readable from below, stamped
on the rear stiffening rib of the rear axle housing."
This number will be of the form:
A2816 - transmission type
1 or 2 - 1= normal differential; 2= ZF limited slip differential K - Model Year
88 xxxxx - five-digit serial number
Pages 30-0102 - 30-1003 of the WSM refer.
Glenn E
'80 928 Petrolblaumetallic 'S' look
5 speed
Sydney, Oz
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MB-Baureihen ca. ab 1981 geeignet :
W107 Roadster 280SL 300SL / W124 / W123 / W126 S-Klasse 380SE / 190 W201 / C-Klasse ?
das W 4 A 040 4-Gang Automatik-Getriebe wurde übrigens auch im Porsche 928 verbaut