diff... In 4x4 mode, you'll have at least one front and one rear wheel
Not really a completely true statement. With Posi on the rear both rear
wheels will spin together not one.
Also I was operating in "O" or "3". I understand I should have gone down to
"2" or even "1". When the rear wheels spin, it reduces power was available
to the front axle. (Like with an open diff one wheel will spin and reduced
power will go to the other). I was told, and I don't know if its true or not
that by shifting to "2" or "1" that the power would be split more evenly
between the front and rear axles.
This is my first IFS truck, so I am still learning. I know how a solid axle
4X4's work, as I still have a 80 GMC PU and a 73 Chevy short PU. But with my
burb the front axle has to be working and getting some power, otherwise I
would still be stuck on the beach at Cape Haterras, because there is no way
in Hell that a 2 wheel drive BurB will run on that soft sand.
Me thinks your T-case is fried. They work like auto trannies in that year
(and the later models) and can "half work". You could have it up on the lift
and all four of the wheels will spin, but you put the rears on a dyno and
the fronts against blocks and it wont pull it's self out.... This is if you
have push-button, which I believe you do. If it's a shifter on the floor you
still have a problem but no idea what.....
I don't understand what you are talking about, when you say it is like an
auto trans. What do you mean? That it has a planetary gear set like an auto
trans does? I thought all the modern T-cases have planetary gearset. Mine is
a NV243, an electric shift version of the NP241C/NP243 which is a descendent
of the NP208. The planetary gearset which controls the hi-lo ratio is in a
direct line, isn't it. If it works, it works. If it slips, both the front
and rear will slip. If it doesn't work, then nothing works. Right? What do
you mean that it can only "half-work"? As long as the chain isn't broke
power will go to the front when It goes into 4hi or 4lo. If the chain is
stretched then there will be noise as it slips, right? It should be a
mechanical connection and either work or not work. If it doesn't work then,
I should still be stuck as power only to the rear wheels won't get it out of
the soft sand.
As I said I don't understand what you are saying would you please explain,
so I can understand.
Bingo. What chain? It's got a clutch pack that practically burns it's self
out. If there is improper preload on the thrust bearing on the differential
that supports the front drive shaft it puts undue pressure on the t-case and
burns it up. It's just like an auto tranny, it spends all it's time killing
it's self. Not only that, but in 2x4 the front wheels are supplied about 5%
power all the time - which doesn't help them much either.
I'm no expert, but I can only guess your pack is slipping just enough to
help you out in some places and just enough that they can stay still in
BTW: Your contradicting yourself. If it was a chain a minimum of 3 wheels
have to spin on your truck in 4xAnything in any gear. If you only have two,
then something is wrong.
Wait a minute! Read the post! I have a NV-243 transfer case. It is not an
"Active on Demand" system, and it is not a "Progressive on Demand" system.
From NV web site "It is an aluminum chain drive transfer case, with
planetary gears.....Being a part time setup with a centered rear output, the
chain is only in operation when four-wheel drive is used.....". " the NV-243
is an electronically shifted version of the NP-241".
You are right about one thing, You are no expert.
No, certainly not. I state this every time I open my mouth. I broker
electronic parts for a living - I'm by no means a wrench. This is just what
I have read from this news group. Take it with a grain of salt, or post a
new thread to see what the others think (this is too far down for most
people to bother).
Well how about this.
Why aren't your front wheel(s) spinning, because your t-case is working
I doubt it.
The AutoTrac t-case in my old '00 S10 ZR2 was chain drive... I haven't
peeked inside the old Avalanche but the new Silverado SS's AWD t-case is
still chain drive. It has a viscious coupling inside the 'hub' or gear
that drives the chain.
When you select AutoTrac on one of the regular late model trasfer cases,
it's still splitting power 50/50 full time - it's the front diff that
engages/disengages the power from the front wheels...
(In 4HI and 4LO, the t-case and front diff are both locked in.)
I hear you... It's just that the G80 isn't all the most reliable thing out
there, and mine has been known to spin only one wheel at times.
I haven't heard that... My understanding is anytime you're locked down
in 4HI or 4LO, you get a 50/50 split of power.
Even with AutoTrac engaged, the transfer case is still locked down 50/50.
It's the front diff that unlocks the axles from the carrier, which is what
AutoTrac uses when it senses that it needs power up front.
I'm not good with old 4x4 stuff. :) I agree with getting out of there in
2wd - it sounds like the same conditions we have. The sand is like flour.
No matter if I am right or not about the clutch packs (which I know I read
about, and I know someone here had to have them rebuilt, and I know I read
that it's cause is incorrect trust-bearing adjustment in the front diff) the
question still remains;
Are his front wheel(s) not spinning because his t-case/4x4 system working?
I think not.
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