constant drive differential unit - advice/experience please

[70Hardtop]

Edit: I added this comment later: The following post is mostly rubbish, so don't read it, I did some research and the question asked is null and void.

As most people know, virtually all differential units that are not 'open' types are LSD type / SureGrip / PosiTraction etc, in that they drive one wheel only in normal conditions and when required by slippery conditions, torque is transferred to the other wheel.

I like the idea of both wheels having constant drive. And I am looking for a unit. I know the Detroit Locker is one of these but it is also quite noisy for normal street driving, which is what I do mostly. (Challenger 340 with 8.75). Backlash and going around corners etc

Recently I made the mistake of buying an Eaton TrueTrac (helical gear type LSD) thinking it was a constant drive unit, because I listened to an 'expert' doing a video on YouTube which said "it supplies power to both wheels all the time until one wheel spins faster than the other (eg turning a corner or under slippery conditions) and then one side unlocks as required"

This guy runs an after market differential place for 4WD mostly so I thought he would know what he was talking about.

For use in an 8.75, does anyone know of any other units that supply constant traction to both rear wheels, other than the old Det Locker? What about the Richmond LockRite? Or maybe I should just admit defeat and use the normal SG unit.

Thanks for any ideas or experience. (please don't just say, "use a SureGrip" because that is not constructive - I am looking for people's experience with a street friendly constant drive unit - if they do exist)

 

[Adam]

What do you not like about the sure grip? And the true trac? Do they not provide torque to both wheels? When you jack it up both wheels spin the same way.
The sure grip and similar units use internal friction to provide torque to both axles; the true trac has no mechanism inside of it to “unlock” one side, so that doesn’t sound right...

I have installed and use a Lockrite in one of my trucks, and I like it, but it’s ratcheting sound and operation would not be my first choice for a street car.

Have you considered an air locker that you can turn on when you need it?

 

[rbbruno3]

I have a Detroit trutrac in my 83/4 I like no issues

 

[70Hardtop]

Well I should cancel that original post, as I made a mistake. I just brushed up on differential theory and looked at a Chrysler Corp. video on open diffs and the SureGrip theory of operation and I can see I was only true in half my post, the rest is crapadoodle. Somehow I had it in my mind that an open diff only drives one wheel. But it actually drives both and splits the torque evenly to both wheels, even when turning. It's only during conditions where one wheel is on a different traction surface to the other (spinning faster), that this doesn't happen. I thought it was only a locker type diff that drove both wheels together with equal torque. So the guy in the video was right, the TrueTrac does behave like a standard diff in normal driving conditions. So for people driving on good roads normally, or even hard on the throttle, (but with no tyre breakoff or spin), the open diff will work fine for this. And an LSD or Suregrip behaves like a normal diff under most normal driving conditions, driving both wheels with equal torque, except when one wheel spins faster than the other.

So I have bought a clutch type SG unit from Doctor Diff and am returning the Eaton TrueTrac for a refund. I would love to use it as the design is genius and they lock up hard and virtually instantly and have no wearing parts. However the unit I received had excessive play in both side gears and would have been noisy on coast and throttle off coming to a stop. This is a known problem and many people have complained about the noise. Basically the axles wobble around inside the unit (when under no load) and this is transferred to the wheels and wheel bearings which wear out three times faster than normal due to the wobble at the wheels. I spoke at length with Cass from Doctor Diff and he said he has seen many TrueTracs with this issue and is considering pulling them from his stock, ie not selling them anymore, until Eaton can come up with a solution. The Mustang guys with them in the 9" and Chrysler 8 3/4 are most affected. Many people who have them, and would hear the noise would probably think it was part of 'normal operation'. It doesn't affect how they operate, it just makes them noisy when coming to a stop or low speed throttle off coast.

I have rambled on enough, thanks for reading, if you have gotten this far.

 

[rbbruno3]

I don't have that problem with mine, must be lucky I guess. I love mine