rear end question??
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TECH Resident
Joined: May 2006
Posts: 858
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From: SoCal
rear end question?? I really dont know a whole lot about rear ends, I will be buying a 12 bolt with 4.10's in the future but I dont know what the diffrence is between posi, detroit locker, and full spool, can someone please explain?? 
Posi means positraction. Different companies call it different things......posi, limited slip, tru-trac, sure grip. They're all the same, positraction, meaning equal power is supplied to both rear wheels. During a turn, depending on the posi unit, there are either clutches or springs or whathaveyou inside your rear, that slip, (hence 'limited slip') and allow the inner wheel to turn at a lower RPM then the outer wheel. Detroit locker is a name brand, but usually what a real Detroit is, is an acutal 'locker', meaning both wheels are locked together, without any slip at all. They are only good for dedicated drag strip race cars and off-roading. You don't want that at all, unless it's a pure race car. Spool, I don't actually know, but I'm sure someone else will post up soon.
Posi units employ clutches to enable the rear wheels to rotate smoothly around corners. A Tru-trac employs a clutchless gear system to do the same (a better option since it doesn't wear out). I'm running one of these in my 9 inch. A locker is as described above and has a ratcheting mechanism to enable somewhat smooth (and noisy) cornering (I wouldn't run it on the street). A spool locks the axles together and is intended for drag racing.
FYI - A 12 bolt is lighter than a 9 inch. A 9 inch is stronger and you can remove the center section to change gears.
FYI - A 12 bolt is lighter than a 9 inch. A 9 inch is stronger and you can remove the center section to change gears.
