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what are the best types of rear ends? Locker or Posi?


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I purchased a ford 9 Inch open rear end.  I am looking to convert it to a posi.  Who has used a locker?  a Posi?  Thoughts on living with a locker rear end?  

 

I am not considering a spool in that this is a street car.  I don't want to spend big bucks but i would like to have better traction than an open diff.

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I purchased a ford 9 Inch open rear end.  I am looking to convert it to a posi.  Who has used a locker?  a Posi?  Thoughts on living with a locker rear end?  

 

I am not considering a spool in that this is a street car.  I don't want to spend big bucks but i would like to have better traction than an open diff.

 

Horsepower?

Transmission type?

Gear ratio?

Type of driving or racing?

 

Personally I would not want a locker in my Mustang.  I have one in my trail rig and it is streetable, but not street friendly.

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351 Cleveland 2v small cam. 330 or so hp. T-5 transmission. Convertible. Not a daily driver. For fun. Looking at 3.70 gear in 9 inch. 245 60 15 tires rear. Might go up in size. Driving. Weekend fun. I am leaning to a stock style posi. But considering lunchbox locker.

 

 

Sent from my iPad using Tapatalk

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I'm running an Eaton posi unit in a 9in with 3.25 gears. It was a good price and have had no issues with it. It's quiet and smooth. I didn't plan on doing any racing and it seemed to fit my needs and budget.

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Personally I would avoid a locker.

 

With a manual transmission every time you shift it unloads and loads the locker, causing it to be even more cantankerous then it is with an automatic. If you liked to drag race, or like to screech tires when turning sharp under power, then a locker would be OK

 

I'm a fan of torque biasing differentials like the Detroit true trac or a quaife. They don't have clutches to wear out and give you good traction without the bad manners of a locker.

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+1. Locker is not what you want. I'm running a T5 with 3.70 gears and a standard traclok. Works great and the gear match with the T5 is spot on in my opinion.

73 Grande H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

 

- Jason

 

 

082-hot-rod-power-tour-2017-1970-1970s.jpg

 

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I have a locker and have had several clutch-type posi-tractions. I never cared for the posi-tractions, seems like the clutches would break loose to one wheel or the other when I needed them the worst.

 

The locker is positive and when it locks up when you get on it going around a corner things can get exciting, depending on how heavy your foot is on the gas pedal. Plus, they can be a little noisy.

 

If I ever get something else it will be a Truetrac, smooth and quiet, no clutches to wear out.

 

You can read about them here (a PDF download):

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.eaton.com/ecm/groups/public/%40pub/%40eaton/%40per/documents/content/ct_128302.pdf&ved=0ahUKEwiErsTez53TAhXiyFQKHZGMAfwQFghBMAI&usg=AFQjCNE12_V7vTYOO3yJcw1O1qf6NlzDAg&sig2=kLNhP7I3xAaDJ9okcWRUig

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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My Mach is in the shop right now, took it there today. I'm having them install a true trac w/3.50 gears. Should be done tomorrow & I'll let you know what I think.

I'm changing the gear from 3.25 to the 3.50. I know its not much of a difference, but I have heard others say its a really great all around gear. I figured since I was getting the posi might as well get a little snappier gear too.

John - 72 Q Code

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For the street I don't think that you would want a Locker. Making turns on the street under power would cause the rear to bounce because the wheels will be turning at the same speed but the distance each wheel travels will be different. This would be good for drags in a straight line.

 

Posi traction or Limited slip are the same. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels. When traveling in a straight line, where one wheel starts to slip (and spin faster than the wheel with traction), torque is reduced to the slipping wheel and provided to the slower wheel. In the case when the vehicle is turning and neither wheel is slipping, the inside wheel will be turning slower than the outside wheel. In this case the inside wheel will receive more torque than the outside wheel, which can result in understeer.

 

With the Truetrac it operates as a standard or open differential under normal driving conditions which allows one wheel to spin faster or slower as necessary. When a wheel encounters a loss of traction the gear separation forces take effect and transfer torque to the high-traction wheel.

 

I went with the True Trac and like it a lot. No issues so far running 3.89 rear. Here is a good explanation on how they work.

 

-john

(jbojo)

351C 4V cc heads, 10.5 : 1 CR, 290 Herbert cam, Flat top forged pistons, forged connecting rods, Atomic efi,

C6 with Gear Vendor overdrive, 3.89 Tru Trac, Hooker Super Comp with 2 1/2" Pypes Exhaust.        

 

Some Mod pictures can be seen at: [button=http://www.7173mustangs.com/forum-garage?filterxt_uid=2026]Bojo's Garage[/button]

 

 

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My Jeep has lockers in both the front and rear. But they are 'selectable' so I can turn them on and off the locking action, it is GREAT offroad. If you want true positive locking action for straight ahead launch it might be the way to go. In the Mustang I run a posi and have good luck with it. I have not used an eaton and have no input good or bad on them.

'Mike'

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

 

Pics of modifications included in: [button=http://www.7173mustangs.com/thread-1973-convertible--3335]My Garage[/button]

 

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I'm running an Eaton posi unit in a 9in with 3.25 gears. It was a good price and have had no issues with it.  It's quiet and smooth.  I didn't plan on doing any racing and it seemed to fit my needs and budget.

 

I second this... I have an Eaton Detroit TrueTrac with 3.50. Yukon gear set. Its a planetary helical type. Works like an open rear until you get on it.

1973 H Code Convertible - Medium Copper Metallic - June 8, 1973, Built Ford Marketing Sales Vehicle

DSC_0266xsm.jpg

satellite.png Proud Space Junk Award Winner!

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I have a Trac-Lok in my 73 and a Tru-Trac in my 69. Both are quiet and work very well, but I would give the TruTrac the advantage since it does not have clutches that would require replacement when worn.

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My Jeep has lockers in both the front and rear.  But they are 'selectable' so I can turn them on and off the locking action, it is GREAT offroad.   If you want true positive locking action for straight ahead launch it might be the way to go.   In the Mustang I run a posi and have good luck with it.   I have not used an eaton and have no input good or bad on them.

 

Mine, too - but rear only (I got distracted by the Mustang before I pulled the trigger on the front axle locker).  I have a Detroit in the rear of mine, and even with 33" tires and 4.10s, that thing pops and clicks going around corners.  Just like bentworker said, every time you push the gas then the clutch pedal, you'll feel the locker load up and unload - which can sometimes happen rather violently.  The first time that happened reminded me of the noise my transmission made when it completely grenaded on the freeway one day - scared the livin' sh!t out of me.  My buddy just laughed at me, "Oh - so you DO have a locker."

 

I have to agree with the consensus - posi might be your best bet.  Hope this helps!

Eric

mach1sig2.gif

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Thank you Midlife for bringing a new perspective to the conversation, I concur.

 

Track Lock is cheaper than eaton style and while it does require proper set up and additive, it can be very durable. Rebuild of the track lock portion isn't really that difficult.

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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I just got back from picking my car up from the shop. Oh yaaaa love the gear change & can't hear the true trac at all. I can tell a difference going around a sharp turn. Rear end stays planted and no more sliding. I can't say much more cause I only drove it about 20 miles home. I need to put 100 or so miles on it to break in the gears, so I didn't really get on it.

I'm happy though. :D

John - 72 Q Code

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I've had Ford Traction Lok's and Detroit Lockers, but I believe I like Midlife's version better, although some of them can be a little on the "High Maintaince" side! (My ex immediately comes to mind)!   :whistling:

Steve

 

No Officer...I really don't know how fast I was going, my speedometer stopped at 140!

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I prefer this style of rear end...

 

 

Exactly what I was thinking, but didn't go there. Well done you "old bugger"

 

There are way too many lobs of a softball on this forum for me to be quiet... :thankyouyellow:

 

 

 

Someone has to do the dirty work, I suppose...

Let me check your shorts!

http://midlifeharness.com

cactus.jpg.92e5d9d8700abc0ed60c8ccb3426248e.jpg

 

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Midlife, Thanks for bringing some humor to this somewhat staid group. We could use some more humor from the original forum joker, Roy are you reading this?  Chuck

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While I can not view Midlife's picture, I suspect that sort of rear end is most prudently acquired via a short term rental agreement rather than a purchase agreement. The long term costs are prohibitive.  Chuck

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