Packard Forum Index » Pre-War (1899-1942)

I have been told there are identifying stamps on the rear end somewhere showing the axle ratio. 4:6, etc. darn if I can find them. Has anyone seen this stamp and where to look for it?

Thanks!

On my 38 the stampings were at about the 2 o'clock position near one of the bolt holes.

Stamped on the flange of the differential housing, about 2/3 of the way around from the pinion. Also they often stamped the actual gear tooth count which you'll have to divide out to get the ratio. Your car (a Super Eight open car, right) probably has a 4.41/1 differential, so you might find the numbers "75-17".

The 5.08 would be 61-12
The 4.07 would be 61-15
The 4.36 would be 61-14
The 4.69 would be 61-13 or 75-16
The 4.06 would be 69-17
The 5.07 would be 71-14

Not all were available in all chassis and body styles.

Tom,

My mate Wade has 2 '34's but he couldn't find any markings on the diff centres externally to identify the ratios in use. He also has a '37 Super 8, similar diff I think, which did have an external marking of 469 which was assumed to be the actual diff ratio. However on counting the teeth on the crown wheel(59) and pinion(12 teeth) that gave a ratio of 4.92:1. And a close inspection of the crown wheel shows the numbers 59 and 12 stamped into it.

My '41 120 also has the number of teeth stamped onto the crown wheel, see very blurry pic. And I think, although memory is dim and I don't have a pic, that it also had markings externally on the diff centre which were correct for the 4.36:1 ratio.

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Its 4.41.

I think this car would go well with 4.06!

Yes Tom, 4.41 is what I suggested your car would most likely have. If it were my car and was going to have a reasonably steady diet of touring with much Interstate driving, I'd go for the 4.06 or 4.07, whichever Phil makes. You'll do a bit more downshifting on some grades but overall should be very pleasant.

Yes, this car will have a steady diet of touring and I need the option of hitting the highway. 4.06 is in the future, but a tonneau windshield is needed first...the 1 and 3 year olds are getting too much wind in the face. Thats another topic.

Terry C, I remember your car having nice gearing, but I did not take note of the what the rear is. Do you happen to know?

Tom