489 case difference

[Roughbird72]

I got my two spare 489 cases out of the loft to set up another third member.
I never noticed this & I've had these cases for awhile.
One doesn't have a lower drain back from the front pinion bearing.

 

[Richard Cranium]

Hmmmmm. Any particular year between the two?

 

[moparnation74]

I have never noticed that either....wonder if the one without was an early case??

 

[Roughbird72]

I will have to find/look at the casting dates

 

[Roughbird72]

The case without the drain back hole(left) appears to be cast differently.
It has 1781 below the part number & 000 by the 9 cast in it.
The numbers on the other case are not legible.

 

[Budnicks]

I wonder if Cranky knows ?, he's been pretty good on this subject...

I wonder if the one with drain back was just a later design
like someone said already

I was told by someone that truck & car pumkins/carriers
had a different design at one time too,
no pinion snuber provision org. trucks too...
Don't quote me on that,
not sure if it is correct, but the guy really was a Mopar encyclopedia...
Not sure it pertained to the 742 or the 489 or both case styles either...

Now I'm curious

I have an older SA Performance rear end/axles/differential/drivelines book,
maybe it will cover it, I don't remember seeing it thou...

anyway carry on

 

[Cranky]

Tried to enlarge the pic but couldn't get it large enough to be able to see if the older looking one is an 88 case but they both were made during the same years and some came with the 1 3/4 large pinion but non tapered. Never seen one nor have I see one without the drain back channel....sorry.