Hi Guys,

I'm trying to figure out what's wrong with my 98 GMC Sonoma. 4.3 liter
auto with electronic 4WD and about 165,000 miles.

I have a wheel locking up. It seems to be one of the front ones. I
tried having my girl friend drive it slowly will I watched and of
course I couldn't tell which one. Looked in my Haynes manual and it was
no help. Just to make things worse I'm broke.

I jacked up the rear and the wheels turn as far as the differential
will allow. Pads and rotors look OK. Parking brake seems to be
released.

Pulled the fuse on the ABS because I've been told they screw up
occasionally. No Luck.

Jacked up the right front and the wheels do not turn freely. The brakes
look OK. The 4WD seems to be engaged and keeping the wheel from
turning. Double checked that 4WD was disengaged ( or the 2 wheel drive
light was on anyway ). The front axles should turn when the 4WD is
disengaged right?

Called my local mechanic and he said it sounds like a transfer case but
he doesn't work on them. Claimed that all he knew about them is that it
costs a whole lot of money to fix them.

The truck will have to be towed to a shop and I hate to have somebody
tear into it without having a rough idea of what's wrong and how much
it will cost.

Anybody else had this problem or have any ideas as to what else I can
check before the old Gal leaves behind a tow truck? Any help would be
appreciated.

Thanks Ozark

Look up front - there's going to be a vacuum pod with a cable on it. See if
you can squeeze the pod, pulling in the cable. That's the thing that locks
up your front diff.

It almost sounds like a CV shaft may have croaked too. Don't see them lock
up very often, but it can happen.

Unless you've done CV's on a 4*4 before though, you'll be getting it towed
in regardless.

Oh yeah, you could always drop the front drive shaft (easy job) and see if
things free up. At least that will eliminate one half from the other.

"Ozark" <donc314 (AT) hotmail (DOT) com> wrote

Ozark wrote:
What do you mean "seems" to be one of the front ones? If its locked up, you
should be able to tell which one is not turning. Your front axles won't
turn freely even though its not in 4WD. If you have a wheel dragging, it
will be hot to the touch after driving a couple hundred feet. On the
front, check that caliper bolts are not rusted; on all four check for
leaking wheel cylinders or grease on the shoes or pads. If they look wet or
(very) dark, fix the leak and do a brake job.

Replies in line...


"Ozark" <donc314 (AT) hotmail (DOT) com> wrote

What caused you to make this diagnosis?

I
The parking brake only works the rear brakes.

Do they turn at all?

The brakes
They should turn as freeely as the back at least. If they spin completely
around, but drag, then I would bet you're looking at a brake problem. If
the 4WD drive was engaged, it shouldn't turn completely around.

Double checked that 4WD was disengaged ( or the 2 wheel drive
Can't help you on cost ideas. I am just a shade tree fella.

As others have said, check to make sure your caliper bolt/pins are cleaned
and lubed. Make sure that the rotors are not discolored (sign of heat.)

I have almost zero experience with the electronic transfer cases, but aside
from the control being electric, I BELIEVE that they mechanically function
the same. As a previous responder noted, dropping the front driveshaft will
definetly eliminate the transfer case from your troubleshooting list.