1966 rear diff - Impala Tech
Transmission & Driveline Transmissions & Differentials

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post #1 of 12 (permalink) Old 06-10-2018, 08:45 PM Thread Starter
 
 
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1966 rear diff

Recently discovered that the 10 bolt in my 66 is toast. I’m not going to dump money into that, but instead have sourced a 12 bolt
The issue I have is that it’s from a 67. From what I’ve found, it should fit into my car without modification. However, it appears that the upper control arms are longer on the 66 vs 67? What arms need to be used to make this work? Is the frame mounts different between the years or are the axle attaching brackets different? I already know that I need to add a 4th arm. Anybody done a swap like this before? Just trying to cover all the beses before I commit to buy the 12 bolt
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post #2 of 12 (permalink) Old 06-10-2018, 09:29 PM
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Use the control arms you have now.

Big Dave
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post #3 of 12 (permalink) Old 10-31-2018, 08:30 AM
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Hi dave am doing the same swap going from a 10 bolt to 12 bolt so tail shift and brakes are all the same from 10 bolt to 12 bolt.

thanks.
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post #4 of 12 (permalink) Old 10-31-2018, 10:23 AM
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Correct

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post #5 of 12 (permalink) Old 11-01-2018, 08:11 AM
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Check the pinion angle on your 10 bolt and verify the 12 bolt matches when installed. If it doesn't the other control arms may be needed or you may need adjustable control arms to get the angle right.
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post #6 of 12 (permalink) Old 04-17-2019, 02:54 AM
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hi can any one tell me the flange measurement from top hole to hole is it 3.375 on a 1966 12 bolt diff.
do a disc brake swap on the diff and using a mbm dbk1012 kit

thanks
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post #7 of 12 (permalink) Old 04-17-2019, 11:13 AM
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All Spicer rear ends (10 and 12 bolts) use this axle flange:



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post #8 of 12 (permalink) Old 04-17-2019, 08:17 PM
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Dave if you look at this pic there is 2 types cheers
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post #9 of 12 (permalink) Old 04-17-2019, 08:47 PM
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You do not want a 12 bolt out of a truck. Uses different gears, has different axles with bigger bearings (hence the difference in size) to carry more weight (the purpose of a truck). Oh and the truck 12 bolt uses a different posi that will break first time you try to launch with slicks.

So since there is no use for a 12 bolt out of a truck except to put in a truck I didn't include it. Just use the dimensions for the car 12 bolt.

Big Dave
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post #10 of 12 (permalink) Old 04-18-2019, 11:03 AM
BA.
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I swapped my single upper arm 10 bolt for a 12bolt about 2 years ago. (clutch dump burn-outs caused the pass. side axle tube to break its' spot-weld and rotate, which moves all those suspension mounting points. Really bad juju)

I used my stock lower control arms but I boxed them in and I had happened to order the Hotchkis adjustable Uppers, which also ensured proper pinion angle on my lowered ride. Great product from them BTW.



Hopefully you're replacing those control-arm bushings while you're at it on anything you re-use!

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #11 of 12 (permalink) Old 04-19-2019, 03:02 AM
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BA I'm replace everything and boxing the control arms also just got a rear disc brake kit Rebuilt the 12 bolts with 3.55 and Eaton truetrac and new Adjustable Panhard rod also. once that's all in will start on the LS swap.
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post #12 of 12 (permalink) Old 04-19-2019, 10:27 AM
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Rebuilt the rear susp on my 67. Boxed the lower arms. Global West adjustable uppers. GM rear sway bar. Hotchkiss panhard bar.
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