I have been having some 4x4 problems with my 2000 Silverado. This
year while plowing snow it wouldn't shift into 4wd correctly. It
would get "stuck" between 2hi and 4hi. It would be in 4hi (front
driveshaft turning) but seemed as though the front wheels would give
any spin. After a couple of trips into the Chevy garage, they finally
changed the encoder (transfer case) motor. The switch was replaced a
year ago and tested fine now. They also tried swapping out the tccm
but that didn't solve anything. Most recently, they replaced the
transfer case moter. Now it shifts in and out of 4wd fine but there
doesn't seem to be any power going to the front wheels. I can shift
it into 4hi and drive across a wet field and get stuck when I could
normally make it without any problems. Something is still not right.
Any ideas? Anyone else have this problem? What's the fix?
I would rec checking your transfercase fluid condition for poss-clutch
material or burnt fluid causing a slip condition/if servicing your fluid
be sure to use GM Autotrac fluid only/hopr this helps russ
There is no clutch material to burn out in that style Tcase. I tend to
call push button 4x4 drive "Push and Pray". There are two elements or
things that need to happen for 4x4 drive to work. The first is the
encoder motor which can be troublsome at times especaily as they get
older needs to shift the Tcase. The second is there is a servo motor
driven actuator on the front axle located on passenger side of
differential. You need to check to set if it is getting power or not
and if it is getting power if it is working. I have plowed snow for
over 20 years now and myself I would never own or use a push button
4x4 for this because you can see the frustration it can cause when it
does not work. I use manual shift Tcases so that the only weak link is
the front axle disconnect on my newest truck with is a 2000 K3500.
(old style or non Sliverado)
Thanks Snoman. The encoder motor is new. There is power to the front
shift motor in the differential and I can hear it when I shift. How
does that actuator work? Does it push in and out? How do I test that
motor to see if it is operating correctly? Thanks!
On 1 Apr 2007 09:49:48 -0700, firstname.lastname@example.org wrote:
It is pretty easy to test it. Simply slect 4x4 drive and then stop
vehicle and with it idling in park with E-brake set, jack up one front
wheel and try to turn it. It should not turn. If it turns without
driveshaft spinning then the disconector/actuator is not working. If
it turns and turns front driveshaft with it then the Tcase is not
being properly shifted or has a internal problem.
On 2 Apr 2007 09:10:24 -0700, email@example.com wrote:
Not is the sense that it is a friction clutch device. The encoder
motor shifts the Tcase internal to engage a splined clutch to lock
front output shaft to drive source, This is aided by a syncronizer.
Based on your problem it is one of three things. Either the encoder
motor is not properly shifting the Tcase range selector internally,
there is a internal failure in the sliding spline clutch and
syncronizer or the chain that drive the front output shaft has failed.
I would suspect the encoder shifting first. BTW, you should have a
your veh should be either a nvg236 or 246 it does appear to have a clutch
pack assembly according to GM. these are right out of a gm repair manual,
I would highly rec fluid drain and refill if never done. its a rec service
and cheaper than a teardown $$(18) Clutch Hub
(19) Clutch Oil Restrictor Plate
(20) Clutch Hub Retaining Ring
(21) Clutch Backing Plate
(22) Clutch Press Plate - Friction
(23) Clutch Press Plate - Steel
(24) Clutch Shim
(25) Clutch Spring
(26) Clutch Pressure Plate Retaining Ring
(27) Clutch Pressure Plate
(28) Clutch Pressure Plate Bearing
(29) Clutch Outer Support
(30) Clutch Assembly Retaining Ring
(31) Planetary Gearshaft Retaining Ring
(32) Thrust Washer
The automatic 4x4 NVG 246 has a clutch pack in it, the 236 does not.
One way to figure out if you have a 236 or 246 is that the 236 uses
ATF fluid while the 246 uses syncromesh fluid which tends to be purple
(assuming it has been properly serviced in the past) also if it is a
246 it will have a "auto" selection while the 236 will not. If it is a
246 I would not be surpruised if it failed because it was not designed
for the rigors of snow plowing. BTW, GM official "SI" dealer service
manual calls for Tcase replacement not rebuilt whith a major internal
failure. IF it has failed I would look for a aftermarket rebuilt
Ah....look at that! More Snojob bullshit! I've rebuilt plenty of
these t/cases.....SI does "not" call for replacement over rebuild.
In fact, GM's warranty policies call for us to rebuild units in
most cases. Only if the cost of the internal parts will go over
the cost of a replacement, do we install complete units. Which
only makes financial sense...has nothing to do with whether the
parts are available, or if we can rebuild or not.
Dealership technicians are some of the few technicians left
that actually overhaul and rebuild components. Mainly because
that's what GM wants as per their warranty wishes. Many
non-dealer shops simply do not have the tooling or knowledge
and so install rebuilt units, or farm their work out.
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