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Discussion Starter · #1 ·
Hello all, i hope this message finds you all well,

I wanted to share some pictures of a crack i have in my differential casing where the drive shaft links in. I apologies if my terminology is wrong, after some research i feel that is indeed the problem area. I've attached some pictures, unfortunately with the oil leak it's not to easy to see, if need be i can clean it up, get it lifted and take some better pictures. In short, i was hoping someone here can provide some insight on what needs to be done to fix the issue. To me, it seems like the entire case needs to be replaced.

Side note, i love this car
Side side note, where is the stamp to find out my gearing, i have a 3 speed manual. I heard 3 speeds only came with 2.73 and 3.07?


138559

138553
138554
138555
 

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Good Looking '70 (y)

I would be surprised if it wasn't your pinion seal.
Clean it real good and get a closer/better look.


138560
 

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Standard axle for a 3 spd manual was a 3:55. With air, 3:23. Could go all the way up to 3:90 or 4:33.
Stamped code is on the left axle tube facing the rear. You'll probably have to scrape some paint to find it.
 

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I'm not seeing a crack, I'm seeing a bad pinion seal leak. Take some Brakleen and spray the area clean for proper inspection. I'm sure you will find no crack.
 

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the stamp should be between the 46 49 circles facing due rear in Jr's picture
4" ish left from the center housing ...
I wouldnt dig for it ,,,, your diff is real rusty under the paint and they are a lite stamp ,,,very similar to the engine code stamp
I would clean super good around the 10 bolt cover edge
so no or less debris will fall inside when cover is removed
and scrub the front pinion leak as described above...
SOAK the fittings on the rubber and steel brake line fittings with liquid wrench a couple times also ,,, because someday youlle need them apart too maybe mmm
then clean real good around the diff oil filler hole too...ALL around
the pinion seal needs to be done by someone in the know
Ive done a couple with no issues but theres a couple tricks
looks like u joint time also while its out ,,, clean and wire brush the drive shaft ,, be nice to it ! its a 1 of a kind length and front yoke,,,
the gear ratio TOOTH COUNT is stamped on the ring gear edge
by the date and part number ,,, buy a real gasket so they dont just silly cone the cover on ,,, buy spicer ujoints too ...
your probably REAL low on diff oil ,,, its been leaking a LONG time
the 10 bolt holds just over a quart of oil only
time for a tranny drain and replace too
use DINO only based lube ,, no sin-thetics

Scott
 

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Discussion Starter · #6 ·
Standard axle for a 3 spd manual was a 3:55. With air, 3:23. Could go all the way up to 3:90 or 4:33.
Stamped code is on the left axle tube facing the rear. You'll probably have to scrape some paint to find it.
Good thing it doesn't have air !
 
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