1978 Chevy 4x4 1/2 ton

[zerozero]

I was wondering, this truck is always in 4x4, there is no way to shift the
transfer case out of 4x4, I was wondering if there was a way I could disable
the 4x4 for better fuel economy without removing the driveshaft.

thanks

[el Diablo]

<abomb69(zerozero)@comcast.net> wrote in message
news:gKudnTjpJLQ...@comcast.com...

I believe you can put manual lock out hubs on a 1978 Chevy.

http://www.windrockoffroad.com/FINDVM/Chevrolet%20Pickup/1/16/36/42/index.htm

Brian

[Spud]

There is probably nothing wrong with the transfer case- the New Process 203s
are just a REAL BITCH to shift and the linkage rods inside can be stripped
if you really force the shifter.

When I first bought my truck 10 years ago I thought mine was frapped too, a
logger friend hopped in and it actually shifted like silk for him, whereas I
hadn't been able to get to square one with it. Admitted I still find
occasionally mine will lock up in 4WD and it can be a frustrating experience
to release it.

I replaced my NP203 once with a Lo Miles rebuild,( 3 man job to lift and
bolt in), it was exactly the same to shift as the original, I had wasted my
time and money.

If the driveline is stock it's probably a full time 4WD (No manual Warn
hubs on front wheels) and will cost you about 1-2MPG over a selective part
time 4WD (with manual or automatic hubs) to run.

First of all, lube up the exposed linkage on the upper right side of the
transfer case, check to see that the linkage is adjusted correctly and that
the plastic bushings are not worn through, there are two holes in the
shifter linkage frame that a drill bit should slide through frame-linkage
and other side of frame when adjusted correctly in neutral 2WD

Once that accomplished, FIDDLE with the shifter while you reverse at least
50 ft., foreword a similar distance, all the time the vehicle is moving you
are trying to gently bump it out of 4WD, when the driveline torque is
eventually eliminated it will POP out. My 78 chevy3/4 ton (same transfer
case) has always been FUN, sometimes I speedshift from HI to LO 2WD
sometimes I have turn the engine off and crank the starter to get it into HI
or LO, sometimes I have to HOLD the shifter into 4WD-LO over some washboard
before it will stay in 4.

You can remove the front driveshaft and leave it in 4WD,that will work, but
if you put it into 2WD the planetary gears in the transfer case are unlocked
and the front shaft stub only will spin, and the rear driveshaft will not
turn.

In order to convert the New Process 203 to part time 4WD you have to buy a
kit for the transfer case differential and install the locking hubs on the
front axle. Warning though, with the NP 203 converted to part time it
doesn't get full lubrication and MUST be run once every 1000mi or so in 4WD
to give ALL the bearings a good splash of fresh oil.

Remember keep fiddling and fiddling with the old bugger and it will probably
surprise you by complying.
Those NP203s were used by Ford, GM, and Chrysler, they are lying around
allover the country, worth about $50.00 - if you can get that much, (do you
want one?)
and you probably know someone (farmer, hunter, logger, etc.) who knows these
200lb cast iron beauties well enough to give it a good "talking to", after
that, you just practice till you figure out what it likes and doesn't like
to do.

If it's truly locked up you might try jacking up one wheel, get someone to
apply shifter pressure while you rock the wheel back and forth, there may be
water inside and the dogs could be rusted to the shaft.

Let us hear how you make out.
Spud

"el Diablo" <nom...@spam.not> wrote in message
news:DeadnU0TwfE...@giganews.com...

[Spud]

More info:

http://www.off-road.com/chevy/mm-np203/

http://www.4wheeloffroad.com/howto/47538/

You can find a lot of info by entering "NP203,NP_203, or New_Process_203"
into Google Web, then Images, then Groups.

Spud

<abomb69(zerozero)@comcast.net> wrote in message
news:gKudnTjpJLQ...@comcast.com...

[Mad Dog]

You can install a part-time kit in the transfer case and shorten it's
lifespan
or swap it out for a NP205.
The 203 is a full-time case which spins the front shaft constantly.

--
Mad Dog

<abomb69(zerozero)@comcast.net> wrote in message
news:gKudnTjpJLQ...@comcast.com...

[zerozero]

I checked on what you explained to do to get it out of 4x4, but the transfer
case just doesnt have 2HI in it, the selector knob only reads 4h-N-4L, and
it only clicks three times starting with 4h then back to the seat for 4Lo
this truck is a gas drinker, I think it gets about 40miles to half a tank of
gas.

"Spud" <ve7ifd...@telus.net> wrote in message
news:7eRVc.46492$fz2.33879@edtnps89...

[Tony Kimmell]

Best way to do it is to drop the NP-203 transfer case and find an
NP-205 to put in it. Then go buy a set of lock-out hubs and install
them on the front axle.

Tony

<abomb69(zerozero)@comcast.net> wrote in message news:<PLGdnZ90PZq...@comcast.com>...