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Hi Guys, Just wondering if anyone has a 65 Riviera PosiTraction Diff they want to sell.
I think they came out in 3.07 and 3.23 ratios so I'll need to know that.
PM me if you like
Thanks

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Hi Tony,

  As I`m sure you know the positraction option can be found with a 3:42 gear or could be combined with any ratio when new...unless I`m unaware of some exception. I currently own a `66 full size Buick equipped with a 2:78 posi as per the build sheet. Best to decide what ratio you ultimately want as that may affect which posi carrier you need. The carrier for a 3:42 gear is different as compared to the carrier for a 3:23 gear...unless you want to get into spacers, etc..

Tom Mooney

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Thanks Tom, I wasn't aware of that.

I'll work out what ratio I need.

From what years can I fit a 65 Riv diff housing? For example would you 66 2.78 center fit in my housing?

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27 minutes ago, fatbuick said:

Thanks Tom, I wasn't aware of that.

I'll work out what ratio I need.

From what years can I fit a 65 Riv diff housing? For example would you 66 2.78 center fit in my housing?

NO...Buick changed to a different type of diff which is not a drop out center starting in `66. I`m positive the `63-`65 diff centers will interchange and possibly earlier. I have seen conflicting info regarding number of axle splines for earlier side gears which would be a disqualifying factor but if I had to venture a guess I would think a `62 diff center section would also work, BUT THAT IS A GUESS.

Tom

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The side gears on a '62 are 31 spline as opposed to the '65 Riv. which is 30 splines.  So in Tony's case it would be '63-'65 Full Size & Rivs. I have a brand new never used  '65 Posi  Carrier for 3.42 & up gears all the way to 4.45 gears.

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54 minutes ago, telriv said:

The side gears on a '62 are 31 spline as opposed to the '65 Riv. which is 30 splines.  So in Tony's case it would be '63-'65 Full Size & Rivs. I have a brand new never used  '65 Posi  Carrier for 3.42 & up gears all the way to 4.45 gears.

So I could transplant my 3.91 ring and pinion into your carrier, and use the housing and axles that are currently  in my 64 with its 3.07?

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Possibly ED as I bought it for my '64 then fond out by using the 4.45 gears I wouldn't make it to the end of the 1/4 mile before the engine ran out of RPM's.   It was over $300.00 with my shop discount. I think retail it was around $400.00 + dollars.

Over the years I have found out it was for a '65, but that it should fit in my car.

I talked to Tom Mooney about it & he told me that it's a one year or so only & VERY RARE especially being NOS.

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3 hours ago, telriv said:

Possibly ED as I bought it for my '64 then fond out by using the 4.45 gears I wouldn't make it to the end of the 1/4 mile before the engine ran out of RPM's.   It was over $300.00 with my shop discount. I think retail it was around $400.00 + dollars.

Over the years I have found out it was for a '65, but that it should fit in my car.

I talked to Tom Mooney about it & he told me that it's a one year or so only & VERY RARE especially being NOS.

Hi Tom,

  I remember you and I speaking about the case but I dont remember why I suggested it was a one year only case? I would think the case would work on `63-`65 diffs as we know they are interchangable.

  It is rare to see an NOS diff case to come on the market. Having said that, as you well know and better than most of us, there are many more parts to the posi diff besides the case. I have most of those parts that I have collected over the years and would be interested in buying your case. I`d like to build a 3:91 diff to have on hand in case I have the opportunity, in my retirement,  to do some drag racing !

  Please send me a message with details if the diff case is available, thanks,

 

Tom M

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