Re: Lockers

["Bill Thebert" <bthebert@domain.elided>]

John Hofstetter wrote:

> I would add 
> that a locker, even one as severe as my Detroit Locker can contribute to 
> axle survival since the torque is always being applied to two axles 
> rather than just one. 

Well . . .
We hashed this one out at GREAT length in Tech Talk a while back.  Torque
is sorta like water pressure in a way.  One needs something to react
*against* in order to develop torque.  Lift one tire in a Detroit-locked
axle and you will develop the full driveshaft torque (x4 owing to the ring
& pinion ratio) on a *single* axle shaft.  You will develop virtually ZERO
torque on the airborne or tractionless axle shaft.

An open differential is actually the great "torque equalizer".  Torque will
always remain precisely EQUAL on both shafts.  Unfortunately, in the
one-tire-airborne case above, they will be equal at nearly ZERO.  Both axle
shafts will receive the amount of torque required to rotate the mass of the
tractionless wheel/tire.  Given good traction at both tires, however, each
axle shaft will normally experience (driveshaft torque x4) / 2 .

I think we concluded that a locker will subject an axle shaft to greater
absolute torque loads; but that an open differential may subject an axle
shaft to more sudden and violent *variations* in torque load -- if driven
with less than great care.

The URL for this message thread (now in the Tech Talk Archives) is:

http://www.binderbulletin.org/cgi-bin/archive_new.pl?read=

There's way more insight from lots of different folks than I can summarize
here.

> Bill T. 
> What is your experience with the long term effect of lockers on wear in 
> the differentials?

I'm not quite sure how to answer this . . . for the locker *is* the
differential.  Or at least a replacement for the differential.  So "what's
the long-term effect of lockers on wear in the lockers"?  I've noticed no
particular increase in wear on carrier or pinion bearings;  nor on the ring
& pinion gears themselves.  I've broken a few front axle shafts -- but
ironically never while driving the truck under its own power.  Always while
flat towing.  Have never broken a rear axle shaft in the Dana 44 -- though
I've switched out a couple of shafts "preemtively" -- as I observed the
splines to be "twisted" into something of a "J" shape.

Hope that helps.

In a coupla hours I'm blasting off Eastward for the Nationals.  I'll be out
of touch for the next 5-6 days.

Regards,

Bill Thebert
The Binder Bulletin


P.S. -- "NATIONALS NEWS FLASH"

In the past month or two I've installed both the Warn Full-Floating Rear
Axle Conversion AND the Front Wheel Hub Conversion kit.  Both are featured
in the October Binder Bulletin, and I planned on discussing these
conversions in one of the "Tech Seminars" at the Nationals.

When I told Warn about this, they GAVE me a $595 Rear Axle Kit to use as a
"visual aid" in the seminar, and told me I could do whatever I wanted with
it afterward.  Since I already have mine installed, we'll be giving this
one away as a DOOR PRIZE.  Folks who attend the seminar (probably Sunday)
will be entered in a drawing for same.  Maybe we'll sell some additional
chances/tickets to raise some cash for my favorite charity -- the Arthritis
Foundation.

In any case, this is one helluva door prize.  Courtesy of Warn and the
Binder Bulletin.  If it goes well, maybe we'll be able to do it again --
either at RMIHR '99 or at the next Nationals.

Bill