12 bolt question

[bad72c10]

Hey guys, has the GM truck 12 bolt rearend changed at all over the years? For example, could I buy a posi carrier out of any GM TRUCK 12 bolt and put it into my rearend? And, I would need a 3.42 or 3.07 carrier because I just bought 3.73 gears for that carrier, so is that a series 3? Thanks, Justin

[71chevylowrider]

I'm no expert, but I did learn a few things while searching for a posi (limited slip) carrier for my 12 bolt rearend on my 71

an eaton series 3 goes from 3.07 up to 3.73
a series 4 goes from 3.73 up to I think 4.56

there was some other posi carriers out there I think they called them a series 80 or something along those lines, they are not the same as an eaton unit & have alot of little parts in them that usually break. also 12 bolt car carriers are not the same as 12 bolt truck carriers so their not interchangable. I hope this helps a little.

[Slammed70]

Dont want to highjack your thread....but while were on the topic.

Where can a person buy a limited slip assembly for a truck 12 bolt. Looking through JUGS or Scrummit all I see is car 12 bolt.

Thanks,
Mitch-

[GREASEMONKEY72]

Originally Posted by Slammed70

Dont want to highjack your thread....but while were on the topic.

Where can a person buy a limited slip assembly for a truck 12 bolt. Looking through JUGS or Srummit all I see is car 12 bolt.

Thanks,
Mitch-

might want to try jegs instead

[KFreddy]

Originally Posted by Slammed70

Dont want to highjack your thread....but while were on the topic.

Where can a person buy a limited slip assembly for a truck 12 bolt. Looking through JUGS or Scrummit all I see is car 12 bolt.

Thanks,
Mitch-

Try these guys http://www.drivetrainspecialists.com/

I had a great experience with them, these are also the guys that built the rearend Dana60 for Project Copperhead. They will be able to answer any and all rear end questions almost before you can ask them And their prices are spot on...

[gregbr]

Series 3 is 2.76-3.73 & Series 4 is 3.73 and higher. I think on the series 3, there is something different about using above 3.42 toward 3.73. Don't use a "cam lock" style from a later truck, they are known to break. Place a wanted to buy ad on the parts board for the series you want or check E-bay. Here is a site for new ones.... http://www.drivetrain.com/eatonposi.html

Greg

[KFreddy]

Originally Posted by bad72c10

Hey guys, has the GM truck 12 bolt rearend changed at all over the years? For example, could I buy a posi carrier out of any GM TRUCK 12 bolt and put it into my rearend? And, I would need a 3.42 or 3.07 carrier because I just bought 3.73 gears for that carrier, so is that a series 3? Thanks, Justin

Yes a 12 bolt truck carrier from any GM TRUCK will bolt in. Newer trucks have a provision for an ABS sensor however that would not effect you at all. A series 3 carrier could be used with 3.73 gears however i would double check with the vendor that they are 3 series carrier 3.73 gears and not 4 series carrier 3.73 gears. There is some overlap between the two carriers specific to certain manufactures.