1957 fleetwood carrier casting numbers

[pozest80hd]

hey there everyone on this forum, I have been pulling out my hair trying to figure out which rear pinion seal to use on my 1957 Fleetwood, the raised casting numbers on the carrier are 1463118 and a little plate with to screw bolts next to it with 2n12. the diameter measures +\-  3.75''_ for the seal opening. I cannot find a seal with corresponding casting numbers. it is stamped with a 6 so I know it is 336/1 ratio rear. I am not sure if this is original rear but I believe it to be. any help on this would be greatly appreciated. and thanks for allowing me on this forum  jp

[J Kjerrulf]

Hi JP, I believe any Cadillac seal from the series 62/60 1956-1959 should do the job - but I don't know for sure.
The 3.36 final gear ratio was optional, but was installed on cars of the series above when ordered with air conditioning.

When found my 57 had "modern" tires so 3,36 was a pain on the highways, after switching to 8.90 things feel better!
And "JP", I think the admins here would appreciate if you sign your future posts according to the forum rules..

[pozest80hd]

thanks for the heads up on the signature. I should have read the rules better.
what I really am trying to achieve with this post is to try and find an answer to what the casting numbers I attached  mean (speak to me as if I were a child) I understand what pinion seal to use and that #6 ratio was a option for the car and yes my car has factory a/c. I was just trying to confirm what the casting numbers mean. and if  within their sequence , somehow reveal that I am running a 1957 year original differential, and if anyone knows what the numbers really mean in breakdown form. just trying to learn the most I can of my car.   thanks for your help.   j stone

[David King (kz78hy)]

The 146xxxx number is a Cadillac part number and most part numbers on a 57/58 start with that number.  The part in question is probably just the differential housing P/N.  These were not listed, not at least in my 1963 Master Parts List, just the assembly number which starts with 351xxxx and would be the GM division which made the rear end.  I don't have my list handy, but probably Saginaw Gear.

Since the housing has 146xxxx on it, it is correct for a '57 model year car.

Does this answer the question?

Good luck.

David

[pozest80hd]

David,
thanks for the info, and I saw exactly what you were looking at with the part numbers as a whole unit.
I will go with it being a 1957 and measure the seal for proper size when I pull it
I did find with further searching the Axle Type is Semifloating  and the Differential is Hypoid   with a Differential Ratio of 3:36-1. so I guess that is a knowledgeable start. last question on this, do you know if these are posi rears or slip disc?  thanks again for taking the time to answer what I was asking.  j stone 1957 fleetwood

[David King (kz78hy)]

That is a open rear end, controlled (posi-track) was not available until '62.

[pozest80hd]

thanks David I really appreciate your time and answers on this.   j stone