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06-05-2007, 08:19 PM | #1 |
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Location: KINGSPORT,TN.
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12 bolt posi I.D. INFO HELP
I was going to swap the rear cover from a spare rear end onto my work truck ( 1971 12 bolt ) and when i removed the cover off my spare rear ( 1970 gmc w/leaf spring, 12 bolt ) the diff looks completely different than the open diff in my work truck. along with the cross pins for the spider gears it has 2 or 3 small pins that run between the carrier halfs and they have what looks like weights or something on them. is this a factory l/slip or posi . never seen one before. if it is i,am gonna swap it into my work truc 12 bolt. the rear covers are the same but the posi cover had a magnet from the factory on it inside. any help is appreciated. also if its a 3.08 gear ratio will my 3.73 gears work on it ?
bob Last edited by BCOWANWHEELS; 06-05-2007 at 08:20 PM. |
06-05-2007, 08:40 PM | #2 |
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Location: Ohio
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Re: 12 bolt posi I.D. INFO HELP
Sounds like it is a posi unit.
3.08 will not interchange with 3.73 without a spaceror the use of aftermarket extra thick gears. If you swap it in make sue you buy the posi additive to go in your gear lube
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06-05-2007, 11:30 PM | #3 |
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Location: Eastern - Manitoba Canada, Winnipeg
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Re: 12 bolt posi I.D. INFO HELP
If it looks like a posi like this style, it's a gov-lock style, it will work until it goes ka-boom, not the recommended style for these older trucks.
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Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife. |
06-06-2007, 01:03 AM | #4 | |
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Re: 12 bolt posi I.D. INFO HELP
Quote:
A posi is going to have the side gears held by 2 plates and 4 heavy duty springs.
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06-06-2007, 02:41 PM | #5 |
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Re: 12 bolt posi I.D. INFO HELP
rod thats it .... think it will hold up on a stock 350 for highway use ? no hi-perf tire spinnin stuff, its just for my work truck. and lastly are they different for 3.08 and 3.73 gear sets ?
thanks bob |
06-06-2007, 03:28 PM | #6 |
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Re: 12 bolt posi I.D. INFO HELP
Bob, you can swap the gears, it will be a "3" series carrier.
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