Hi Don,
I had some opportunity to study the parts fiche for the M45 and M46 take-off gears.
Speedometer Drive Gear Part Numbers
teeth | axle | M45 | M46 |
---|
16 | 3.15 | 1220257 | -- |
17 | 3.31 | 380978 | -- |
18 | 3.54 | 380979 | 380754 |
19 | 3.73 | 380980 | 381681 |
20 | 3.91 | 1220484 | 380753 |
20 | 3.31 | -- | 380753 |
I have some vague recollection that an explanation exists for the 20-tooth gear being used in both 3.31 and 3.91-equipped M46, but I can't recall what it is.
The only two US speedometers I see in both the M46 and M45 applications are those you already mentioned, 0.96 and 0.98. The ratio of those ratios corresponds to the 2% difference between wagon and sedan tires. Not likely to be 10mph at any speed our cars can achieve, but one tooth different at the speedometer take-off could be as much as 7%.
--
Art Benstein near Baltimore
Bakers trade bread recipes on a knead to know basis.
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