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Re: Auto Hubs w/ Lockers




On Wed, 31 Dec 1997 16:05:08 -0500 tsm1@domain.elided (Tom Mandera) writes:
>Just doing some musing last night (gotta stop that)
>
>With open diffs, and AUTOMATIC hubs, I *don't* get compression braking 
>down a hill (or even on pavement, right?) from the front end.  The front

>wheels are allowed to over-run the driveshaft.  This is because if the 
>driveshaft is still, the AUTO must remain in the "free" position.  
>
>*SO*.. because of the auto hubs in my donor '76 Dana 44, I'm 
>considering a Lock-rite (it's all locked or open I guess, and I want all
locked!).
>
>The lock-rite will allow one axle shaft to overrun the driveshaft, but 
>ONE driveshaft MUST turn at the same speed (x gearing) as the
driveshaft.
>
>BUT.. what happens when I'm in 4WD, making a turn?
>
>The inside wheel turns slower, thus the Locker drives the inside 
>wheel. Outside wheel turns faster, overruning... either the AUTO hub 
>overruns, or the Lockrite overruns.. not sure which will happen first.
>
>This will still cause me some bucking around a turn.. inside wheel 
>turning as fast as the rear end..
>
>Originally along this thought I was thinking I'd avoid any bucking.. 
>not true :)
>
>BUT, would replacing the Lock-Rite with a mini-spool make one lick of
>difference?  Obviously putting the hubs in LOCK mode will change
>everything.. ;-)
>
I don't know how how the Lockrite operates, so I'll have to assume it
operates as you describe. 

In the Lockomatic mode, without a locking diff, I don't think you should
have bucking while turning.  Because the rear wheels track inside the
fronts in a turn, the fronts have to travel further than the rears and
they will overrun the axle shafts which must turn at the same speed as
the rear's.  I don't think the addition of the locking diff would alter
this, particularly if only the inner one remains locked as this one
travels the shortest path of all the wheels.  

But I can see that problems could arise due to fight between the two
locking mechanisms.  I've experienced a problem with an open diff when
one hub was locked and one unlocked (unintentionally).  The front hubs
would suddenly begin to chatter--why I don't know, but I knew something
was wrong. I'd think all you've got to lose would be the hubs themselves
so you could try it.   

But I'd think the hubs in auto mode would be even more at risk in
off-road situations where the entire torque could end up going through
one front hub.  I know I was able to split one hub just starting out on
soft grass because the hub apparently didn't lock immediately, a rear
wheel spun momentarily, and the hub grabbed with a bang.  And this was
with a AMC 6-232 at probably 600 RPM, not a dump the clutch start at
higher RPM behind a V-345. 

Howard Pletcher
Howteron Products Scout Parts



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