Author Topic: better option than detroit locker?  (Read 5756 times)

mlplunkett

  • SAAC Member
  • Full Member
  • *
  • Posts: 150
    • View Profile
better option than detroit locker?
« on: January 08, 2020, 10:19:17 AM »
I'm building a 9" axle for my GT350R tribute and remember hearing that the Detroit Locker used in the original cars is not a great option for a street car. Anybody got an informed opinion on the pros/cons of going with an aftermarket locker as opposed to the Ford Traction Lock that was used in other Shelby cars? I do hope to get the car on a road course now and then for some spirited driving but I won't be racing it competitively. Most miles will be on the street. Motor will be a 302 stroker so probably about 400 HP.
67 GT500 tribute under construction
65 R-model tribute under construction

Shelby_r_b

  • SAAC Member
  • Hero Member
  • *
  • Posts: 1906
    • View Profile
Re: better option than detroit locker?
« Reply #1 on: January 08, 2020, 10:50:31 AM »
I’ve got a Detroit Locker from a 65 GT350 in my 66 Carryover, and I love it! You just have to get used to the sounds and pops. But, for wouldn’t trade it!
Nothing beats a classic!

Jim Herrud

  • SAAC Member
  • Full Member
  • *
  • Posts: 105
  • '65 GT350 Tribute, '19 GT350 Eagle ID
    • View Profile
Re: better option than detroit locker?
« Reply #2 on: January 08, 2020, 10:53:37 AM »
Take a look at torque sensing Limited-Slip Differentials (or LSD), also known as torsional differentials. These units sense the torque on the wheel with the least traction and they mechanically multiply that torque to the other wheel. The most popular version seems to be the Eaton TrueTrac Differentials. They get good reviews as being reliable and reasonably priced.

Back in the 80's, I ran a Traction-Lok differential for Autocross, but had to change the clutch-packs occasionally. On my current rebuild, I originally installed a Detroit Locker in my Ford 9", but my project has taken so long to complete that the new torque sensing differentials came out in the mean time. I was told that when using the Locker in a performance situation, the sudden engagement and disengagement can upset the car. In addition, there is a disconcerting "clunk" when the Locker disengages. The torque sensing differentials seem to be widely recommended as superior in most situations.

I chose the Moser Engineering Wavetrac torque-sensing LSD even though it is more expensive because it has a lifetime warranty (regardless of your horsepower!) and it works under no-load conditions when one wheel has zero traction. Since a torque sensing differential multiplies the torque on the lower-traction driven wheel, when that wheel has zero-load, the typical torque-sensing differential provides no torque to the other wheel (because any number multiplied by zero is still zero). This would occur only in rare situations like very slick ice under one drive wheel, or when one wheel is completely off the ground as in rock crawling or track-curb jumping. Under no-load conditions, a typical torque-sensing LSD acts like an open differential, whereas the Wavetrac acts like a spool (both wheels rotate at the same speed). Wavetrac's are popular among the off-road crowd where the Locker is also still widely used.

« Last Edit: January 08, 2020, 11:22:50 AM by Jim Herrud »
Shelby Buff. I'm a driver - Not a docent.
I used to be a “Vintage Car” guy. Now I’m just a “Vintage” car guy.
"There's never enough horsepower - Just not enough traction." - C.S.
Straight Roads are for Fast Cars. Turns are for Fast Drivers.

Royce Peterson

  • Sr. Member
  • ****
  • Posts: 472
    • View Profile
Re: better option than detroit locker?
« Reply #3 on: January 08, 2020, 11:02:58 AM »
Detroit Lockers built in the past 35 years are not like the originals in that they make no noise at all. They are utterly silent yet bulletproof. There are no clutches to wear out. They are available in 28, 31 and 35 spline. For your build I would use a 31 spline unit. 28 spline axles are easy to break even with a small block if you have more than 250 HP to the wheels.

There are still "H" series Detroit Lockers sold mostly to NASCAR and Dirt track racers. These are noisy like the original ones from the 1960's. Often for sale on eBay at very reasonable prices because NASCAR racers replace them every 500 miles. These are typically 31 spline or 35 spline.


I'm building a 9" axle for my GT350R tribute and remember hearing that the Detroit Locker used in the original cars is not a great option for a street car. Anybody got an informed opinion on the pros/cons of going with an aftermarket locker as opposed to the Ford Traction Lock that was used in other Shelby cars? I do hope to get the car on a road course now and then for some spirited driving but I won't be racing it competitively. Most miles will be on the street. Motor will be a 302 stroker so probably about 400 HP.
1968 Cougar XR-7 GT-E 427 Side Oiler C6 3.50 Detroit Locker
1968 1/2 Cougar XR-7 428CJ Ram Air C6 3.91 Traction Lock

gt350hr

  • Hero Member
  • *****
  • Posts: 2111
  • Randy Gillis in real life - 5353 original posts
    • View Profile
Re: better option than detroit locker?
« Reply #4 on: January 08, 2020, 06:29:05 PM »
   mlplunkett,
     You can buy a NEW forged steel case traction lock in the low $300s on epay. This is a very quiet "clutch type" limited slip that will be fine for your use. IF you use the axles with C4OW on the end you will not break them until 400 wheel HP and on a drag strip with the traction lock. Use certainly can upgrade to a 31 spline axle as Royce wisely suggested. I had to switch about 30 years ago in my mid 11 second ( then) '66 Hertz car.  I was fortunate enough to have a pair of genuine '65 A/FX Mustang axles ( 31 spline) and simply switched to a 31 spline locker at the same time. You will have to use an aftermarket axle to get 31 splines.
     Next up would be the Gleason ( true track) and Auburn ( cone type) units . They are also quiet , smooth , and virtually trouble free , especially in a street / cornering application They are also available in 28 and 31 spline.
     "My" last choice for the street is the Detroit Locker , especially with a manual trans. The inherent "play" in the internal gear mechanism produces a noticeable "clunk" when cornering and what road racers call the "locker lurch". Some use this action as a driving aid to set and upset the car when cornering . Others despise it. I have a locker in my automatic equipped drag car because I don't want a "spool" ( it has NO differential action) . Avoid H case lockers ( 31 and 35 spline only) as they require an aftermarket 3.250 bearing diameter aftermarket differential case which is not needed for your use. It is critical with a locker to maintain equal tire pressures and diameters or your car will "torque steer" or worse yet keep the unit engaging and disengaging as you are driving. "Some" of the modern units have an annoying "clicking" noise as they corner at low speeds. Just the thoughts of a guy who's done Ford diffs since '68 when I was factory trained.
      The choice is up to you.
    Randy
Celebrating 46 years of drag racing 6S477 and no end in sight.

s2ms

  • SAAC Member
  • Sr. Member
  • *
  • Posts: 462
    • View Profile
    • 6S1757 Info
Re: better option than detroit locker?
« Reply #5 on: January 08, 2020, 10:43:00 PM »
Been running an Auburn Pro in my 66 for ~20 years, completely satisfied.
Dave - 6S1757

6s1802

  • Full Member
  • ***
  • Posts: 163
  • Mamber since 1981
    • View Profile
Re: better option than detroit locker?
« Reply #6 on: January 09, 2020, 12:56:30 AM »
Be a man, run a locker. Just make sure your rear tire pressures are even or it might throw you around a bit.

shelbydoug

  • SAAC Member
  • Hero Member
  • *
  • Posts: 3991
    • View Profile
Re: better option than detroit locker?
« Reply #7 on: January 09, 2020, 07:54:18 AM »
Be a man, run a locker. Just make sure your rear tire pressures are even or it might throw you around a bit.

If you are into S&M, self torture and mutilation a "Locker" is what you want.


These things are absolutely brutal on a street driven car and it is said that they were never run in NASCAR because if you for some inexplicable reason break an axle, you will spin the car.

I had one in my car for a week. There were several reasons it had to come out. First, I nearly got arrested because it spun the inside tire on a tight left hand turn in a Police directed emergency turn. The local PD can impound the car legal for "street racing" and take a very dim view of public displays of uncontrolled "acceleration".

I was only going like 5 mph, and this SOB spun the left rear tire, leaving rubber and squealing the whole way!



Next, I thought that I ran over a metal garbage can and  broke the rear springs backing out of the garage. I don't need to induce additional paranoiac stresses.

Additionally, you will never get a passenger to ride in the car with you. They will jump out the window screaming that there is something wrong with this car (and obviously you too) and they don't want to die in a crate like that.


I've run the Ford traction-lok and it is much more then acceptable. It is true that it is not 100% efficient because it is a clutch unit and the left only gets about 50% of the power that it should but you couldn't prove that by me. The car lays down a very impressive set of skid marks and no one is going to do a scientific measurement of "power to the ground" measurements on them with the possible exception of the local PD as they prepare evidence against you for your day in court.


The True-track is probably going to be the smoothest and most civil unit you could run but with these cars, do you really want a civil pussy cat?
68 GT350 Lives Matter!

Royce Peterson

  • Sr. Member
  • ****
  • Posts: 472
    • View Profile
Re: better option than detroit locker?
« Reply #8 on: January 09, 2020, 09:05:03 AM »
Bad information - the Detroit Lockers made in the past 35 or so years make no noise at all. Obviously you have not used one or rode in a car equipped with one. Nothing is felt driving on the street, going around corners or not. On loose soil, wet pavement or gravel you will sometimes notice the inside wheel skidding. The identical same thing happens with a Traction Lock that is not worn out, and other clutch type differentials until they wear out.

   mlplunkett,
     You can buy a NEW forged steel case traction lock in the low $300s on epay. This is a very quiet "clutch type" limited slip that will be fine for your use. IF you use the axles with C4OW on the end you will not break them until 400 wheel HP and on a drag strip with the traction lock. Use certainly can upgrade to a 31 spline axle as Royce wisely suggested. I had to switch about 30 years ago in my mid 11 second ( then) '66 Hertz car.  I was fortunate enough to have a pair of genuine '65 A/FX Mustang axles ( 31 spline) and simply switched to a 31 spline locker at the same time. You will have to use an aftermarket axle to get 31 splines.
     Next up would be the Gleason ( true track) and Auburn ( cone type) units . They are also quiet , smooth , and virtually trouble free , especially in a street / cornering application They are also available in 28 and 31 spline.
     "My" last choice for the street is the Detroit Locker , especially with a manual trans. The inherent "play" in the internal gear mechanism produces a noticeable "clunk" when cornering and what road racers call the "locker lurch". Some use this action as a driving aid to set and upset the car when cornering . Others despise it. I have a locker in my automatic equipped drag car because I don't want a "spool" ( it has NO differential action) . Avoid H case lockers ( 31 and 35 spline only) as they require an aftermarket 3.250 bearing diameter aftermarket differential case which is not needed for your use. It is critical with a locker to maintain equal tire pressures and diameters or your car will "torque steer" or worse yet keep the unit engaging and disengaging as you are driving. "Some" of the modern units have an annoying "clicking" noise as they corner at low speeds. Just the thoughts of a guy who's done Ford diffs since '68 when I was factory trained.
      The choice is up to you.
    Randy
1968 Cougar XR-7 GT-E 427 Side Oiler C6 3.50 Detroit Locker
1968 1/2 Cougar XR-7 428CJ Ram Air C6 3.91 Traction Lock

shelbydoug

  • SAAC Member
  • Hero Member
  • *
  • Posts: 3991
    • View Profile
Re: better option than detroit locker?
« Reply #9 on: January 09, 2020, 09:44:25 AM »
Bad information - the Detroit Lockers made in the past 35 or so years make no noise at all. Obviously you have not used one or rode in a car equipped with one. Nothing is felt driving on the street, going around corners or not. On loose soil, wet pavement or gravel you will sometimes notice the inside wheel skidding. The identical same thing happens with a Traction Lock that is not worn out, and other clutch type differentials until they wear out.

   mlplunkett,
     You can buy a NEW forged steel case traction lock in the low $300s on epay. This is a very quiet "clutch type" limited slip that will be fine for your use. IF you use the axles with C4OW on the end you will not break them until 400 wheel HP and on a drag strip with the traction lock. Use certainly can upgrade to a 31 spline axle as Royce wisely suggested. I had to switch about 30 years ago in my mid 11 second ( then) '66 Hertz car.  I was fortunate enough to have a pair of genuine '65 A/FX Mustang axles ( 31 spline) and simply switched to a 31 spline locker at the same time. You will have to use an aftermarket axle to get 31 splines.
     Next up would be the Gleason ( true track) and Auburn ( cone type) units . They are also quiet , smooth , and virtually trouble free , especially in a street / cornering application They are also available in 28 and 31 spline.
     "My" last choice for the street is the Detroit Locker , especially with a manual trans. The inherent "play" in the internal gear mechanism produces a noticeable "clunk" when cornering and what road racers call the "locker lurch". Some use this action as a driving aid to set and upset the car when cornering . Others despise it. I have a locker in my automatic equipped drag car because I don't want a "spool" ( it has NO differential action) . Avoid H case lockers ( 31 and 35 spline only) as they require an aftermarket 3.250 bearing diameter aftermarket differential case which is not needed for your use. It is critical with a locker to maintain equal tire pressures and diameters or your car will "torque steer" or worse yet keep the unit engaging and disengaging as you are driving. "Some" of the modern units have an annoying "clicking" noise as they corner at low speeds. Just the thoughts of a guy who's done Ford diffs since '68 when I was factory trained.
      The choice is up to you.
    Randy

Well, if you are a know it all, WTF are you coming here and asking anyone for their opinions?
Go take your Locker, insert it, and have a wonderful time.

I would think though that if you were making an accurate tribute, then you would want to experience the real thing? Not some teenage virtual reality?
68 GT350 Lives Matter!

gt350hr

  • Hero Member
  • *****
  • Posts: 2111
  • Randy Gillis in real life - 5353 original posts
    • View Profile
Re: better option than detroit locker?
« Reply #10 on: January 09, 2020, 10:57:51 AM »
     Royce YOU are WRONG. "Big spring" ( the kind you are referring to from the last 35 years) lockers CAN make a noise when cornering if they are not under load. Not EVERY one is "silent" regardless of what you say. I have owned and used several of them that made noise "out of the box". The noise is somewhat related to what springs are in the locker and the "clicking is more prevalent in those with softer springs as they disengage easier. I have changed springs to heavier ones ( yellow from Ford Motorsport) and greatly reduced the noise. YES they are FAR better than the '65 units without the "hold out rings" .
  YOU may be lucky in having quiet operation lockers but your experience is not EVERYONE'S experience with a locker. Having one "snap" into locked condition when leaving a stop sign can be uncomfortable. I ran one in my car hauler that had a 14 bolt GM rear for ten years and experienced the "snap" hundreds of times. I eventually took it back out.
  I respect your opinion and experience greatly but there are other experiences and opinions from others like me that is different than yours. Please respect that. If you want to argue with me please go to PMs.
      Randy
Celebrating 46 years of drag racing 6S477 and no end in sight.

Royce Peterson

  • Sr. Member
  • ****
  • Posts: 472
    • View Profile
Re: better option than detroit locker?
« Reply #11 on: January 09, 2020, 04:21:30 PM »
I often get this sort of response from folks who knew a guy who had a trans camaro etc. I invite anyone in the Tulsa area to come try both a freshly rebuilt Traction Lock and a Detroit Locker. I have both. The difference is not evident.
1968 Cougar XR-7 GT-E 427 Side Oiler C6 3.50 Detroit Locker
1968 1/2 Cougar XR-7 428CJ Ram Air C6 3.91 Traction Lock

68stangcjfb

  • SAAC Member
  • Sr. Member
  • *
  • Posts: 250
  • Long Island New York
    • View Profile
Re: better option than detroit locker?
« Reply #12 on: January 09, 2020, 09:21:33 PM »
At the risk of being burned down, I'll take a crack at this being that I had a 28 spline early 80s Ford Motorsport 4.11N case Detroit Locker in my 4225 pound with me in it '67 Fairlane 428 4 speed station wagon for 8 years. Do you know its back there compared to a traction lock? Yes. The way the car comes out of turns is a little different from a traction lock. I know that because I have a traction Lok differential in the car now with 3.89 gears. Does it make a lot of noise? The one in my car didn't really. Will the car make turns if you snap an axle? Yes. I know that because I snapped an axle one time when I dumped the clutch and the car wheel hopped badly. It snapped the left side axle right at the splines. Surprisingly though I was able to drive the car home with the broken axle. I had to take it very carefully because if I gave it a lot of gas accelerating the car, it wanted to make a left turn but I still made it home without a tow truck. The next day, I pulled the axle out, took a long magnet, pulled the broken piece out of the differential, installed another axle, and then called Dutchman axles and ordered a set of alloy 28 spline axles and haven't had that problem since. Why did I pull it out of the car? Because at the time I installed 3.25 gears so I can drive on the highway and turn 3000 rpm at 75mph. I put the 3.89 gears in because I could at least go 63 miles per hour at 3000 RPM as opposed to 56 miles an hour at 3000 RPM with the 4.11s. Would I put it back in? Yes. That's my humble opinion. Others may have different opinions.
68 1/2 CJ Mustang GT FB auto 3.91s, 68 1/2 CJ Torino GT FB 3.91s, 2 57 Thunderbirds, 60 Thunderbird, 64 Falcon Sprint conv. 4Spd, 65 Falcon Sedan Delivery, 67 Fairlane 500 SW 428 4Spd, 68 Torino 4dr, 95 Thunderbird SC. My 58 Thunderbird got rear ended by a RETARD on his phone!!

1109RWHP

  • Hero Member
  • *****
  • Posts: 541
    • View Profile
Re: better option than detroit locker?
« Reply #13 on: January 09, 2020, 09:41:11 PM »
I had a NASCAR locker in my 70 and it was brutal. I had a street version in a 64 Comet for years and it would make noise every now and then but was no big deal. I did notice it had more drive train slack when getting on/off the gas though. I took the NASCAR locker out and installed a torsion style instead. You don't even know it is there. I think for road racing the torsion will apply the power smoother in the turns over a locker. Why use old school technology when there is better stuff out there?

gt350hr

  • Hero Member
  • *****
  • Posts: 2111
  • Randy Gillis in real life - 5353 original posts
    • View Profile
Re: better option than detroit locker?
« Reply #14 on: January 10, 2020, 11:07:22 AM »
I often get this sort of response from folks who knew a guy who had a trans camaro etc. I invite anyone in the Tulsa area to come try both a freshly rebuilt Traction Lock and a Detroit Locker. I have both. The difference is not evident.

   Royce I have LITERALLY installed over a thousand Detroit lockers and just as many traction locks. A Detroit Locker has FAR more "play" in it's internal gears than a traction lock ( none). That play is VERY noticeable when turning and getting off and on the gas as opposed to a traction lock because of that internal gear play. I don't need to go to the Tulsa area to experience that. I have cars with both in my driveway right now. You have your opinion and others have theirs. I don't see what "folks who knew a guy who had a trans camaro" has to do with anything. If you are referring to those with opinions that have never owned / driven a car with a locker , that is NOT me. I have installed Detroit Lockers in AMC, Chrysler , Ford, GM, and Toyotas. Their operation is all the same , just different packaging. Try all you want but you will never convince me there is no discernable difference between driving a car with a Traction lock and a Detroit Locker. This is NOT ANY kind of personal attack! My experience is simply different than yours.
   Randy
Celebrating 46 years of drag racing 6S477 and no end in sight.