How to ID a posi-trac? Options

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Guest		#1 Posted : Thursday, 28 December 2006 1:58:33 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		G'Day, Had this disscussion in another thread but never really solved my question. How do I ID a genuine Posi, & is it a type of salisbury diff? Is there any way to tell from the outside weather it's a 10 bolt or a 12 bolt....? The Beige Hornet.

Guest		#2 Posted : Thursday, 28 December 2006 4:02:31 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		I take it that you mean an HK to HG Salisbury type differential, or do you just mean LSD. Positraction is a term used by GM for LSD and as HK to HG are the ones with US sourced LSD then these are the only true positractions used by GM-H. With this in m

ozchevy		#3 Posted : Thursday, 28 December 2006 6:57:09 AM(UTC)
Rank: Member Reputation: Groups: Registered Joined: 12/10/2005(UTC) Posts: 495		Posi-traction diffs are a three piece housing which includes integral cast iron differential carrier and housing with pressed in and welded steel tubes. Semi-floating forged and heat-treated axle shafts. Wheel drive flange is forged integral with the a
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Guest		#4 Posted : Friday, 29 December 2006 5:42:05 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		So if I've got this right then 10 bolts around the rear plate is a 10 bolt & 12 bolts around the plate is a 12 bolt, but the name refers to the bolts holding on the crown wheel. Does Salisbury just mean the style of diff with the rear cover-plate as o

FastEHHolden		#5 Posted : Friday, 29 December 2006 5:49:03 AM(UTC)
Rank: Member Reputation: Groups: Registered Joined: 13/01/2006(UTC) Posts: 303		My guess is that its worth a fair bit to the Monaro nuts out there..it would probably go a fair way to getting a BW78 or 9 inch with what ever brakes you want.
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ozchevy		#6 Posted : Friday, 29 December 2006 8:40:11 AM(UTC)
Rank: Member Reputation: Groups: Registered Joined: 12/10/2005(UTC) Posts: 495		Yes Hornet, 10 bolts on cover equals 10 bolt crown wheel, and the same as for 12 Bolt. Salsbury is the name given to the gearing - Hypoid Differential carrier. Don't under-estimate the durability and strength of a Posi-traction. These diffs will well and
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Guest		#7 Posted : Friday, 29 December 2006 10:13:49 PM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		The only problem with the HK salisbury, as far as power is concerned, is the axle shafts are designed for 6 cylinder wheel bearings. As ozchev said, they are dam strong, probably stronger than 9", but axles fail. Solution is to fit 9" axles for high

Dr Terry		#8 Posted : Saturday, 30 December 2006 2:11:44 AM(UTC)
Rank: Veteran Reputation: Groups: Moderator, Registered Joined: 1/03/2005(UTC) Posts: 6,114 Thanks: 1 times Was thanked: 219 time(s) in 199 post(s)		Hi Guys. The ID of the 9" rear axle bearings is the same as the Holden 6 & V8, at 1.378". The Ford bearing is actually about .040" narrower as well. It's the axles themselves, AFAIK they are Australian made, whereas most 9" axles are US made to suit Bi
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Guest		#9 Posted : Saturday, 30 December 2006 2:14:11 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		Thanks guys, great advice as always. I wont need the axle upgrades just yet as I'm going back to a 186 for fuel economy reasons, but it's nice to know what it is. Was the line in Joe Dirt (?)..."God is like a posi-trac, no one knows how it works, it just

Guest		#10 Posted : Monday, 15 January 2007 1:44:43 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		Was under 'the hornet' today & noticed the numbers 3894859NF cast into the front of the housing on the passenger side - can anyone positivley ID the diff from this? The Beige Hornet.

ozchevy		#11 Posted : Monday, 15 January 2007 5:01:17 AM(UTC)
Rank: Member Reputation: Groups: Registered Joined: 12/10/2005(UTC) Posts: 495		Don't know what that number is, but the one you should be looking for would be something like this as an example "GX G 112 1 E" This is from a 1971 10 bolt posi-traction Breaking that down would go like this, GX = Ratio 3.08:1 G = Plant, Detroit G
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Guest		#12 Posted : Tuesday, 16 January 2007 7:58:05 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		Where on the diff should I look for that? Old mate I got it from said it came from a Bathurst Ed HK. Doesn't look played with, I just want to be sure of what I've got. The Beige Hornet.

Guest		#13 Posted : Tuesday, 16 January 2007 8:18:43 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		Just 'googled' that number & apparently that means it's a 10 bolt cast in 67 - 69. These guys were talking Camaro's, I assume holden imported the housings & put their own axles / tubes in or something...? The Beige Hornet.

Guest		#14 Posted : Tuesday, 16 January 2007 9:22:27 PM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		More numbers if anyone can help. I've discounted the 'test' cast numbers & I'm still left with GM3 cast into the front driver's lowersection of the housing, & more ineresting is at the rear, on a flat surface next to the cover plate '742' has been stamped

Guest		#15 Posted : Thursday, 18 January 2007 8:27:36 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		Sorry, Cast numbers were GM63, & stamped numbers were '8742', & 'L3' upside down - c'mon, anyone got any ideas....? The Beige Hornet.

ozchevy		#16 Posted : Friday, 19 January 2007 2:21:54 AM(UTC)
Rank: Member Reputation: Groups: Registered Joined: 12/10/2005(UTC) Posts: 495		Yes Hornet, looks like a Camaro Posi-traction - I Googled that number as well. It would appear to be a 8.2" most likely a Eaton or GM Posi-traction from what I've just read.
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Guest		#17 Posted : Friday, 19 January 2007 6:32:05 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		Is there any way to tell if it originated as a camaro unit or a HK Unit? I can't see any evidence of the spring saddles being moved & I was told it was from a HK Monaro (obviously I would love it to be the original HK item, but to be sure I have to be abl

Guest		#18 Posted : Friday, 19 January 2007 6:37:10 AM(UTC)
Rank: Guest Groups: Guests Joined: 2/09/2015(UTC) Posts: 43,977 Was thanked: 5 time(s) in 5 post(s)		Sorry OzChevy, forgot to say 'thank you' for taking time out to google the number & come back to me - just had an epiphany, too: maybe it is a camaro unit that has had new axle tubes with the HK sadles installed. That would explain the lack of a the axle

ozchevy		#19 Posted : Friday, 19 January 2007 7:35:37 AM(UTC)
Rank: Member Reputation: Groups: Registered Joined: 12/10/2005(UTC) Posts: 495		Yes that may well be a possibility, tubes changed on an Eaton Posi-traction. Might be quite a unique differential??? Good luck with the sale of it in any case.
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