Factory Locker in Chevy S10 Pickup?
William Yuknis
Hi, I was browsing the dealer brochure for the '97 Chevy S10
pickup. One of the factory options that was offered is
a LOCKING differential!
I was surprised to find this. Does anyone know if this locking
differential is a Chevy design, or some other manufacturer
like Detroit or ARB? Would it be automatic or manual? ANd
how durable would it be (depends on who makes it)?
Thanks.
-- BIll
Reply to: wyu...@NOSPAMsunland.gsfc.nasa.gov
(remove NOSPAM to reply, hate the 'bots)
Tony T.
It is called an Eaton Gov-Lok. It's more of a limited slip than a true
locker, but has characteristics of both. Here's an exert from
http://www.mpis.net/~jshapiro/zr2/faq/index.html that should answer any
questions (this is a little long):
The locking differential in the ZR2 is called an Eaton Gov-Lo(c)k. It's a
hybrid design that incorporates elements from the traditional limited slip
(also called a "posi" or "positraction") and a traditional "mechanical
locker" (brand names like "Detroit" or "Lock Right").
The way it's supposed to work is that when one wheel slips (spins faster
than the other wheel on the axle), clutches in the differential are
engaged. The clutches trigger a mechanical system that solidly locks the
two axles together, preventing one wheel from spinning faster than the
other. The Gov-Lock system will disengage the locking mechanism when torque
is no longer applied to the pinion (the part of the rear diff that is
connected to the driveshaft).
The Gov-Lok differs from traditional mechanical lockers in a couple of
important ways (I'll use a Detroit Locker as an example of a traditional
mechanical locker):
•Detroits are always locked, they unlock when torque is applied by a wheel
being spun faster by the road (i.e. your outside wheel tracking on a turn
causes the diff to unlock, and the engine applies power to the inside
wheel) •Gov-Loks are always unlocked, and the outside wheel on a turn is
the powered wheel •Detroits do not need to sense wheelspin, because they
are already locked - they only sense when the road is making a wheel spin
faster, and then they unlock (usually with a BANG) •Gov-Loks must sense
wheelspin (by the clutch mechanism) and lock when one wheel has gone faster
than the other (the threshold for locking is set higher than normally
occurs in a turn). •Detroits will instantly cause a vehicle to slide
sideways when on an icy side incline •Gov-Loks will let one wheel spin,
then engage the locking mechanism, causing the vehicle to slide sideways on
an icy side incline (audio imitation: whiiiiirrrrr, BANG, sideways
sliiiiiiiide)
Is one better than the other? Not necessarily.
Detroits can cause funny handling characteristics on short wheelbase
vehicles (reference the inside wheel being driven on a turn). Gov-Loks have
a tendency to engage harshly, causing slides and unexpected wheelspin on
both rear tires. Gov-Loks also exhibit a tendency to self-destruct when a
lot of torque is applied to the locking mechanism. (Imagine the force of a
31" wheel/tire quickly spinning up to 30 mph and then the locking mechanism
trying to engage the other axle/wheel/tire which might be barely moving and
on a high-traction surface). The extreme situation like this is when you're
3-wheeling to get over an obstacle.
You can sometimes modulate the locking action of the Gov-Lok by applying
the brakes gently when you're spinning a single wheel (this is also a trick
you can do with a limited slip differential). It sometimes makes the
engagement of the locking mechanism less harsh. My advice is to not floor
the gas when you don't have both wheels on similar surfaces -- you'll be
less likely to have any of the "bad" locker characteristics bite you in the
butt.
William Yuknis <wyu...@NOSPAMsunland.gsfc.nasa.gov> wrote in article
<01bc3c46$b0e7f4a0$d417...@necronomicon.gsfc.nasa.gov>...
Willem-Jan Markerink
In article <01bc3c46$b0e7f4a0$d417...@necronomicon.gsfc.nasa.gov>,
"William Yuknis" <wyu...@NOSPAMsunland.gsfc.nasa.gov> wrote:
>Hi, I was browsing the dealer brochure for the '97 Chevy S10
>pickup. One of the factory options that was offered is
>a LOCKING differential!
>
>I was surprised to find this. Does anyone know if this locking
>differential is a Chevy design, or some other manufacturer
>like Detroit or ARB? Would it be automatic or manual? ANd
>how durable would it be (depends on who makes it)?
>
>Thanks.
>
>-- BIll
>
Must be an Eaton Gov-Lock, one that locks in above a certain wheel spin
rpm.
Real auto-lockers a la Detroit/Lockright have been available at one time in
the past (forgot for which vehicle, anyone?), but that didn't last long.
Even manual lockers are rare, only the Mitsu Pajero/Montero (rear),
4Runner/Tacoma (rear) and TLC 80-series (front+rear) AFAIK.
--
Bye,
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_/ _/ _/ _/ _/ _/ _/
_/ _/ illem _/ _/ an _/ _/ _/ arkerink
_/_/_/
The desire to understand
is sometimes far less intelligent than
the inability to understand
<w.j.ma...@a1.nl>
[note: 'a-one' & 'en-el'!]