Telling the diff
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1970Duster
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Well if its in a Mopar, it's almost certainly an 8.75. Too make sure, look on the drivers side of the center section and the should read 741,742,489.
The phord nine inch has a pinion "plate" on the front of the center section just behind the yoke with five retaining bolts. The 8.750 does not.
67Dart273
Well-Known Member
Sure, easy. But Ford made a SMALLER (8") and a LARGER (some Lincolns) rear (third member type) than the 9", and these are not so obvious
Mopar 8 3/4 is exactly "round."
Ford is "slightly flattened" at top and bottom of housing:
(Read this link)
http://www.kevinstang.com/Ninecase.htm
Ford 9, not all have the "hump" in the back:
BUT THIS is the smaller 8" axle, which looks very much the same:
To tell between the smaller 8" and the 9", look at the bottom nuts on the third member. IF you can stick a socket and extension onto the bottom bolt, it's the smaller 8". IF you must use a box wrench (no room for a socket) it's a 9"
Mopar 8 3/4 is exactly "round."
Ford is "slightly flattened" at top and bottom of housing:
(Read this link)
http://www.kevinstang.com/Ninecase.htm
Ford 9, not all have the "hump" in the back:
BUT THIS is the smaller 8" axle, which looks very much the same:
To tell between the smaller 8" and the 9", look at the bottom nuts on the third member. IF you can stick a socket and extension onto the bottom bolt, it's the smaller 8". IF you must use a box wrench (no room for a socket) it's a 9"
1970Duster
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Not always. I got a 9" center section that came from a Truck and it didn't have it. When I was put the 9" back together in my Ranchero, I took the pinion plate onto the truck one becaue it was a limited slip unit.
Ford did have a 9" with the same two dimples on the back of the housing. My buddy has one in his 340 powered Henry J. We thought it was an 8" until the rebuilder told us it was an early 57-58 Fairlane rear.
Bill S.
Bill S.
abodyjoe
Well-Known Member
the ford 8" also has a drop out center section..
fishy68
Tyr Fryr's Inc.
Say what???? First off all Ford 9" have the pinion support. If they didn't there would be no way to adjust the pinion depth cause it's done with shims behind the pinion support plate. And what's up with that English? Sure not easy to make out what your saying!
1970Duster
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The pinion support wasn't what I was talking about, what I was talking about was this (see picture #1) it has a "cover" over the Yoke, while the other (see picture #2) doesn't have it. The center section that came with my Ranchero looked like picture #1 (it was an open diff), but the one I bought/got out of a F150 looked like picture #2 (this center section had a limited slip diff). So when I went to check it out and seal the center section, I swaped the pinion retainer over the center section with the limited slip and bolted into my Ranchero's rearend housing.
I should've said pinion retainer but for the life of me I couldn't remember what the Ford manual called it at the time.
fishy68
Tyr Fryr's Inc.
LOL... Ok... Just a misunderstanding. Your talking about a shield, not the actual pinion support. I said what I said because Strokerscamp mentioned the pinion support and you said not all 9" rears have it. SS called it a pinion plate but by his description of it being held on by 5 bolts I took it he was talking about the pinion support. Just wanted to clarify that all 9" rears have a pinion support where-as a Mopar doesn't use one.
1970Duster
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Yeah man its all good. When I read what SS posted I knew exactly what he was talking about. I would've called it by it's proper name but lately I've been seriously off my game (guess the holidays are messing with me more then I thought!).
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