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Tail Shaft Diff Flange

Jolls

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Hi Team

I need to tap into the collective knowledge of the forum. I have a VY SS ute I purchased as a project. It has a cammed LS1 and was provided with a an empty VZ M80 diff shell and a 2 piece tailshaft with a solid uni in the centre instead of the donut. The spline mates up to the T56 box and I was advised that I need a 5.0 litre VT diff pinion flange to mate up to the tailshaft.

I have done my research and located a VT pinion flange. However, the VT flange is a 6 bolt flange. The tailshaft is a four bolt (standard VY/VZ is three bolt). Does anyone know what V8 Commodore runs a 4 bolt diff pinion flange? If you do that would be gold!

If you have one to spare that would be happy to part with that would be even golder!

Cheers n Beers
Jolls
 

_R_J_K_

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Just about every VT V6 and V8 flange should be a four bolt, it looks like the 6 bolts were VY/VZ (although probs VT/VX at some stage) 3.46 diffs for Adventras and HSVs. The 5.0 diff would have been an M78 anyway, they didn't use the M80s until the LS1. Sounds like that tail shaft is from a VT S1 (that sounds like what they ran) and the yoke has been changed to a T56 one or the yoke is the same.
 

Jolls

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Just about every VT V6 and V8 flange should be a four bolt, it looks like the 6 bolts were VY/VZ (although probs VT/VX at some stage) 3.46 diffs for Adventras and HSVs. The 5.0 diff would have been an M78 anyway, they didn't use the M80s until the LS1. Sounds like that tail shaft is from a VT S1 (that sounds like what they ran) and the yoke has been changed to a T56 one or the yoke is the same.
Thanks RKJ
This clears up a bit of confusion. I was searching on the net and saw advertised a VT diff pinion flange and it has six holes. This didn't ring true to me so I went back and checked the manual - sure as eggs the exploded drawing of the VT diff shows a 6 bolt flange, which I expect also mates up to a 3 bolt tailshaft. This was the genesis of the question.

After receiving your response this morning I went back through the manual. Sure as eggs the pinion flange is shown as having 6 bolt holes.

1659386492677.png

When I read through the description of the propellor shaft it clearly states that it is 4 bolt.

1659386623016.png


Not the fist time the manual information is either misleading or incorrect (VZ accelerator pedal wiring had me stumped for months as the pins were numbered incorrectly in the manual).

So the question in my mind now is does the 4 bolt flange actually have six holes but only four line up with the shaft. I have now seen a few diff pictures on ebay/gumtree and they seem to have the six hole flange. Two of them are labelled as four bolt. Confusing - I think I need to locate a Commodore wrecker and take the tailshaft down to see what matches what.

Cheers n Beers
Jolls
 
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Immortality

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I've got one in the garage that came off a VR IRS diff as well as one of my old VN. I'll take some pics later for you.
 

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Thanks mate
Appreciate it.
Cheers
Jolls
 

Lex

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Thanks RKJ
This clears up a bit of confusion. I was searching on the net and saw advertised a VT diff pinion flange and it has six holes. This didn't ring true to me so I went back and checked the manual - sure as eggs the exploded drawing of the VT diff shows a 6 bolt flange, which I expect also mates up to a 3 bolt tailshaft. This was the genesis of the question.

After receiving your response this morning I went back through the manual. Sure as eggs the pinion flange is shown as having 6 bolt holes.

View attachment 240788
When I read through the description of the propellor shaft it clearly states that it is 4 bolt.

View attachment 240789

Not the fist time the manual information is either misleading or incorrect (VZ accelerator pedal wiring had me stumped for months as the pins were numbered incorrectly in the manual).

So the question in my mind now is does the 4 bolt flange actually have six holes but only four line up with the shaft. I have now seen a few diff pictures on ebay/gumtree and they seem to have the six hole flange. Two of them are labelled as four bolt. Confusing - I think I need to locate a Commodore wrecker and take the tailshaft down to see what matches what.

Cheers n Beers
Jolls
This reminds me of my vt s1 v6 diff? I'll take a pick & post it tomorrow? I've got m80 LSD 3.46, thats been adapted for that that type of flange.
 

Immortality

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OK, here we go.

Here we have an M80 and M75 pinion side by side. The M80 pinion has a diff flange from a VR (M75/76/78) IRS diff on it.
0-02-07-497d5da3ec933737b5ef750e2a972d290b8cb899395a91dfeaef7628762ae9f7_12ec95c31d4ff2ac.jpg


And with the flanges removed.
0-02-07-3803d3a450b2b201307d1724eaa9392e96a588ff513a39c979be88f96f66c3bd_e98f193691b95ad1.jpg


They have different nut sizes but interestingly my M80 diff rebuild kit came with both sizes.
 

Immortality

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And the important bit, the drive shaft flange.

The holes in the flange are all on one pitch circle diameter (doesn't matter how you line them up, they always line up).

0-02-07-8c35750a67ed3ae2efd4da4c6b8df5ee6a451c2e894a9e39b77e7da7a02e4010_43eaeec908364f78.jpg

And some measurements.

0-02-07-c19f40bc2755634972fb2c2dd4c7126096ef4ba1c55cb6e45cec2ee21967ca1f_933e543b46497f7c.jpg

0-02-07-e240fe1619a1e50347b02fc639910c413c98794d10c941b725a4a48f77a9682b_ecfb088a21b6f836.jpg
0-02-07-5d26eda6c670712814f7c4bb5ac93225a70140ca389514cbce17d0dab9f477ff_3df1f410284d55dc.jpg
 
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Lex

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OK, here we go.

Here we have an M80 and M75 pinion side by side. The M80 pinion has a diff flange from a VR (M75/76/78) IRS diff on it.View attachment 240806

And with the flanges removed.
View attachment 240807

They have different nut sizes but interestingly my M80 diff rebuild kit came with both sizes.
The guy who built my diff, had to cut the m80 pinion down (l think thats the right word part name?), to be able to bolt the vt tailshft (4 bolt flange to it).
 

Immortality

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I just realized I forgot one critical measurement, the ID of the flange where the drive shaft coupling registers, if you need it let me know and I'll measure it tomorrow.

I've been trying to type these posts out for about half an hour but our little kitten doesn't like been ignored. She's dead tired and doesn't like been ignored, my fingers tapping on the keyboard is a great gaem...
 
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