correct pinion seal?
udoittwo
Posted 2018-02-21 10:02 AM (#558551)
Subject: correct pinion seal?


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Location: Valley Forge, Pa.
I have a 1960 Plymouth Suburban with a very slight seal leak. My friend gave me a National seal #5126 O.D. 71.45MM[2.81"] shaft seal size of 47.63MM[1.875"]. It has an outer flange.
Looking on Epay, they show one Timkin #7216 O.D. 76.2MM[3"] and shaft seal also at 47.63MM[1.875"]. Both are listed for a 1960 Plymouth.

The rear is factory. Before I climb under and find I have the wrong seal, which is correct?

Thanks again for your time,
Karl.
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mstrug
Posted 2018-02-21 12:39 PM (#558565 - in reply to #558551)
Subject: Re: correct pinion seal?



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http://www.doctordiff.com/8-3-4-pinion-seal.html

Which case do you have should have a big 2 on the side for a 742 .

http://www.rockauto.com/en/catalog/plymouth,1960,fury,5.2l+318cid+v...

http://members.tripod.com/~Mojo_Page/chry875.htm


1820657 (small stem, up to 1964)
2070741 (small stem, 1965 to about 1972)
2070742 (large stem, 1957 to 1968)
2881489 (tapered pinion, 1969 to about 1974)
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udoittwo
Posted 2018-02-22 6:51 AM (#558602 - in reply to #558551)
Subject: RE: correct pinion seal?


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That's what I don't know. I didn't even realize there are 2 different sizes in 1960. So, bottom line is, I won't know until I get under there?

Thanks for the info,
Karl.
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57chizler
Posted 2018-02-23 3:13 PM (#558696 - in reply to #558565)
Subject: Re: correct pinion seal?



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mstrug - 2018-02-21 9:39 AM

1820657 (small stem, up to 1964)
2070741 (small stem, 1965 to about 1972)
2070742 (large stem, 1957 to 1968)
2881489 (tapered pinion, 1969 to about 1974)


There is another one, 1634985 (large stem 1957 to 1963)
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di_ch_NY56
Posted 2018-04-22 12:36 PM (#562072 - in reply to #558551)
Subject: RE: correct pinion seal?



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A good friend (here in the forum as well, moderator) addressed the correct pinion seal for my Letter. I ordered two and was very, very surprised that it didn't fit. No wonder, the rear axle installed in my 300F (Letter) under restoration is a 8.25 rear axle and not a 8.75 rear axle (#@*&^%!).

Today I purchased a 742 differential (complete) to install into a real 8.75 rear axle. The shop owner showed a possible candidate for the swap. It's a 8.75 rear axle with a 3.23 final ratio. He's the meaning it's out of a New Yorker. What do you mean?

The pinion seal for a 8.25 rear axle is an SKF 18708 pinion seal.

Happy Restoring!

Dieter





(IMG_4915_differential of the swap candidate.JPG)



Attachments
----------------
Attachments IMG_4915_differential of the swap candidate.JPG (180KB - 140 downloads)
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57chizler
Posted 2018-04-22 3:44 PM (#562077 - in reply to #562072)
Subject: RE: correct pinion seal?



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The 1820657 casting IS an 8 3/4".
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di_ch_NY56
Posted 2018-04-23 12:55 PM (#562118 - in reply to #558551)
Subject: RE: correct pinion seal?



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Thanks John

But it's not out of a New Yorker, but it's a Plymouth/Dodge low power version with the small pinion shaft (predecessor of the 741 case). Then it seems that the track is not identical as well (Plymouth 59.2", Chrysler 60.0".

Happy Restoring!

Dieter

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57chizler
Posted 2018-04-23 1:06 PM (#562120 - in reply to #562118)
Subject: RE: correct pinion seal?



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A lot of people seem to think that the small pinion differentials are "weak" because they're the smallest. In reality, all of the straight-stem pinions neck down to the same size so the small stem isn't really that much weaker.
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Powerflite
Posted 2018-04-24 1:10 PM (#562202 - in reply to #558551)
Subject: Re: correct pinion seal?



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Agreed John. You need to have a manual trans and gobs of torque to worry about breaking anything that came in an 8 3/4. Dieter, you need to understand that your gear set could have been swapped out at any point in it's life. That doesn't mean that the whole rear end was swapped too. It could have been, but not necessarily. In fact, it isn't very likely. It is much more likely that someone wanted a different gear ratio and grabbed a gear set to swap into it. If that's what happened, your track width will remain as it always has been from the factory.
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di_ch_NY56
Posted 2018-04-24 1:26 PM (#562203 - in reply to #558551)
Subject: RE: correct pinion seal?



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While cleaning the bumper rubbers and the holders above the rear axle I noticed that at the drivers side the axle had a very severe crash to the rubber bumper. There is even a bump in the holder of the rubber. The installed 8.25 axle doesn't show any damage in the contact area. So it's likely that the original axle was destroyed during that crash.

But a 8 3/4 differential does not fit into an 8.25 axle - I assume...

Happy Restoring!

Dieter

BTW: 1) the first paragraph is about my Letter
         2) the swap candidate has the big (similar to my Letter) brake drums installed. I assume this is the reason, the shop owner was talking about a New Yorker axle



Edited by di_ch_NY56 2018-04-24 1:31 PM
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