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posi unit for 9 inch rear

Discussion in 'The Hokey Ass Message Board' started by 66nova383, Sep 4, 2011.

  1. 66nova383
    Joined: Jun 26, 2010
    Posts: 87

    from oregon

    Looking for recomendations on posi unit for ford 9in.That is in my 51 Austin a40 with small block and 5 spd. this car will be a street strip car. thank for the advice
  2. 61falcon
    Joined: Jan 1, 2009
    Posts: 772


    put a locker in it. i wore out a couple of clutch type 9 inch posi's and finaly put a detroit locker in and wish i had done that from the start. my car also is street/strip.
  3. Normal Norman
    Joined: Aug 9, 2006
    Posts: 510

    Normal Norman
    from Goshen IN.

    I've got a good old Detroit locker in mine. Normal Norman
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 50,967


    I'm running a Detroit locker. Might try a Torsen Tru Trac if I had to do it over again...or maybe not.

  5. seb fontana
    Joined: Sep 1, 2005
    Posts: 7,444

    seb fontana
    from ct

    X2...I ran a locker for years, you get used to the clunks and bangs and lets you chuckle when the noises scares your passenger...When I took out the 5.14's I put in a Ford Traction Lock [smooth unit] with a 4.11 gear, I think Currie is rebopping them..I didn't like the feel of the locker in slow speed sharp turns pushing the front end..
  6. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    from florida

    Whatever you do, don't buy it from a certain "9 inch expert" in Pa. who sells on Ebay. We bought two TracLocks and they both leaked out of the snout right out of the box. He said we overfilled the you overfill a 9 incher I have NO idea. :rolleyes: I've even installed junkyard rears that never leaked.

  7. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 4,008

    from illinois

    I put a powertrax lok-rite in my 8" 10 years ago 32K miles , performs flawlessly, was cheap [relatively] too.

  8. Willy301
    Joined: Nov 16, 2007
    Posts: 1,426


    I put the Ford Racing Trac-loc in mine, I am very pleased. I would say that I had to clearance my housing just a little to clear it as the ring gear mounting boss was a little thicker than the open I replaced. I also had to get the slightly longer bolts for the ring gear.
  9. Deuce Roadster
    Joined: Sep 8, 2002
    Posts: 9,519

    Deuce Roadster
    Member Emeritus

    I have run a Detroit Locker and a both types of the Ford limited slip. The earlier " limited " slip was called a Equa-Lok and the later ones were called Traction-Lok.

    The Detroit Locker is noisy:rolleyes: ( at least mine is ). It sometimes grabs abd clunks when turning slowly. It feels like it is pushing the 32 straight ahead ... not turning.

    The Equa-Lok works smoothly and quietly. It has 7 plates ... and was discontinued maybe 40 years ago. Parts are more difficult to find ( at least around here ). I found the Equa-Lok to wear out sooner than a Traction-Lok.

    The Traction-Lok has one more steel plate and one more fiber plate than the Equa-Lok. It is a newer, improved ( IMHO ) version of the earlier units. The Traction-Loks have more machined surfaces and are easier to get parts and pieces. The Traction-Lok works smoothly also. Both the Equa-Lok and the Traction-Lok require a special Ford Motor Company friction modifier to the rear end lube ( about 7 or 8 dollars ).


    I have a Traction-Lok in my 32 3W coupe ... and you cannot tell it is in the coupe until you mash the go pedal and BOTH the rear tires grab and leave black marks equally. The 32 Roadster has the Detroit Locker :rolleyes: and it is noisy ... and you feel it. It does work GREAT. Just noisy and you can feel it at times. IF I ever break/tear up the rear end of the 32 roadster ( unlikey ) ... I will put a Traction-Lok back in it. For a vehicle with more track use than my 32's ... I most likely would go for the Detroit Locker.

  10. Lucky3
    Joined: Dec 9, 2009
    Posts: 652


    X2.....much better piece and easier on the rest of the drivetrain.
  11. squirrel
    Joined: Sep 23, 2004
    Posts: 50,967


    I guess it depends on the car, in a heavy boat there's no pushing from the locker, and the newer ones are really quiet. If you're not loading the rearend a lot, then a clutch type "posi" should be fine.
  12. boogeracng
    Joined: Feb 13, 2008
    Posts: 345

    from Eureka,MO

    Locker......if you weren't aware, there are a couple of versions. The old style that was available in 4x4's and early aftermarket, and the later version I think is referred to as "soft lock"...a bit softer spring. The internals other than the engagement spring, are the same. It's more street friendly, and isn't quite so harsh in the lock up/turn/disengage mode. This might be a consideration for a light car. I've got one, just updated from the factory and never run, 31 splines. PM me if interested.
  13. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    from MI

    For a Ford 9" you can get pretty much any kind of limited slip and locker there is. Although lockers are tough, because it is possible to apply all the engine's power to just one wheel, they can be more demanding of axle shafts.

    Not cheap, but a Torsen is a good compromise for a street car. Clutch type difs can be adjusted and upgraded if that's what you decide on. Auburn cone type diffs are popular, but they don't seem to hold up well to hard use or big power.
  14. plymouth1951
    Joined: Nov 28, 2010
    Posts: 118


    hi, i see you commented on an auburn clutches. can you elaborate on the use of these. i found one for my 51 plymouth and i was told this was the hot ticket by an old timer if i was to go "drag" racing. it seems less durable visually than a conventional borg and beck type clutch plate. we want to go drag racing a couple times a year with our stock 230 plymouth flat head. does the ol timer make any sense. i have stock 9, 10 or 11 inch stock mopar 50's conventional clutch plates to choose from, or i also have the auburn clutch plate. thoughts?
  15. squirrel
    Joined: Sep 23, 2004
    Posts: 50,967


    The Auburn clutch he's talking about in this thread is not the one between the engine and the transmission, which you're thinking of. It's a limited slip differential, in the rear axle.
  16. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    from MI

    Auburn diffs have threaded tapered cones that wedge in the diff carrier. Pressure against side(axle) gears help wedge the cones against a mating surfaces in the diff carrier casting. Over time the cones and locking surface in the diff carrier casting wear. In ordinary use they hold up pretty well. When used hard the cones and diff carrier wear out faster than the rest of the parts in the diff.
  17. navypainter
    Joined: Dec 3, 2010
    Posts: 73


    I have a 28 Sport Coupe, 350 chevy, 4 speed and a 9". The motor is not a power house (350 horse?) but should move the A along quite nicely. After reading all of the above, Im thinking I should run a Trac Loc as I want to drive it on the street mainly. Any thoughts?
  18. milner3268
    Joined: Oct 1, 2010
    Posts: 283

    from buffalo NY

    I had a detroit locker in my duece and with the weight/wheelbase it pushed the car before it BANGED and unlocked ,put it in my 55 and it worked fine . I replaced it with a detroit trutrack no pushing no noise no rebuilding and will hold all the power you can throw at it .I have been dumpin the clutch in in my coupe at 4000 and 5000 rpms all summer with no issues
  19. johnnie
    Joined: Jan 7, 2009
    Posts: 493

    from indiana

    Just a few notes.
    Traction Lock are fine if ya set correct preload on the clutches.
    A new stronger clutch side "hat" should be used in my opinion (AT LEAST CHECK THE STOCK HAT FOR CRACKS REAL GOOD!).
    Don't do burn outs with one tire in water, doughnuts, etc.
  20. Sheep Dip
    Joined: Dec 29, 2010
    Posts: 1,572

    Sheep Dip
    from Central Ca

    For a street machine Power Lok all the way, I have had these in several rears over the years with no problems or issues. Just my 2 cents worth.:D:D
  21. I've got an Auburn Pro Posi and it works great. Don't even know it's there and always leaves 2 stripes.
  22. You may also want to checkout a DPI gold-track style or torque sensing differential. They have adjustable pre-load and will work very smoothly coming out of the corners. I learned about them from the Quick Change manufacturers - as they supply them to the circle track/road-race guys for both Q.C. as well as 9" rears. Also, they set them up for street cars all the time - and just lessen the pre-load.

    Personally, I can't stand the Detroit Locker -- all that popping and jumping around slow corners drives me nuts. Feels like the U-joint has come apart . . .
    Last edited: Oct 16, 2011
  23. Rebel 1
    Joined: Oct 25, 2010
    Posts: 568

    Rebel 1

    Stay away from Auburn. They don't hold up and can't be rebuilt.
  24. Can you share your experience? Have you actually worn one out?
  25. I have a Torsen Diff in the Divco. Works perfect, not cheap.
    It takes everthing the 502 has, never a problem. All my cars are driven like rental cars, with added insurance !
    Smooth around corners.

  26. young'n'poor
    Joined: Jan 26, 2006
    Posts: 1,280

    from Anoka. MN

    A few of my friends have auburn units in their street machines, 400 to 500hp street/strip cars. Some have been in for 5+ years of heavy abuse and still work like new.
  27. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    from MI

    Per my previous posts about this, and per what others have said, I have seen many worn out Auburns.

    Per my previous post, "In ordinary use they hold up pretty well. When used hard the cones and diff carrier wear out faster than the rest of the parts in the diff."

    Manufacturers like the Auburn. Whether that's because of how they perform, or due to a cost of manufacture, I don't know. As you posted, they do work. But, even on normally driven street cars the friction surfaces wear more than one would like.
  28. bulletproof1
    Joined: Feb 23, 2004
    Posts: 2,080

    from tulsa okla

    have a detroit locker in mine... love it.....
  29. George G
    Joined: Jun 28, 2005
    Posts: 1,274

    George G

    I need a clutch for my ford eqalock. Any suggetions to buy parts?
  30. Gus68
    Joined: Jan 29, 2007
    Posts: 428

    from Minnesota

    OK, This may sound stupid, and I should know better, but i have heard more than once that there is a "poor mans" way of making a non posi 9" into some sort of posi. Has anyone ever heard of this ? Would you just put in an extra shim or 2 in the spiders? I would like to know, I just don't see how it could be done.

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