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Old March 16th 09, 08:49 PM posted to rec.autos.4x4
OzarkMtbr
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Posts: 2
Default Another 4WD question -- 97 Mazda B4000

On Mar 4, 8:11*pm, "Kickin' Ass & Takin' Names"
> wrote:
> I posted earlier about problems with my 97 Mazda B4000 not going into
> 4WD.
>
> When I turn the switch on the dash to 4WD HI or 4WD LO, the dash
> indicator light comes on
> corresponding to the switch position but the truck clearly IS NOT
> going into
> 4WD.
>
> I fiddled around with it today in the garage. When I turn the switch
> from 2WD
> to 4WD, I don't hear anything moving -- as I understand it, flipping
> the switch
> causes a solenoid on the transfer case to activate, engaging the
> transfer case
> into either HI or LO and it seems as though I'd here something click,
> clunk,
> grind, or whatever.
>
> I checked the 4WD fuse in the fusebox under the hood and it's good. I
> pulled
> the fuse out and checked it with my ohmmeter and it's good -- I
> sprayed contact
> cleaner into the slot for the fuse and plugged it back in. No change.
>
> I crawled under the truck. There's a driveshaft coming out of the
> transfer case
> that runs into the front differential and two shafts run from the
> differential
> to the front wheels. I can turn the driveshaft coming out of the
> transfer case
> with my hand -- it turns freely and I see the shafts going to the
> wheels
> turning.
>
> I thought there was something -- vacuum line? -- running to the front
> wheels
> that activates the automatic hubs but the only thing I see going to
> the front
> wheels is the brake line.
>
> And now the 4WD LO light on the dash will not go out.
>
> Guess it's time for a trip to the dealer.
>
> As soon as they get it working, I'm going to replace the automatic
> hubs with
> WARN manual hubs.
>
> Am I right in thinking that the front automatic hubs are engaged all
> the time
> and the only thing that happens when I turn the switch on the dash is
> that a
> solenoid engages the transfer case?
>
> How about I crawl under the truck and whack the solenoid a time or two
> with a hammer?
>
> Thanks.


I had a 98 Ranger which I believe that year was a whole new truck
rework but should have similar hub system. The electric selector on
the dash activates the transfer case which in turn engages the drive
shaft to the front diffy and the drive shafts to the wheels. The hubs
on my Ranger were vacuum activated. You were also required to reverse
10 feet to unwind the hubs after using the 4x4 system. Since all of
the shafts are turning properly, you probably have a vacuum problem.
Either the hoses or vacuum solenoid is plugged up or it is not even
connected as in my case.

The problem with my ranger is that the driver front wheel hub was
always locked. I didn't realize this for a long time. I had been
offroad and my 4x4 was working fine. The problem was when I would be
in 4x2 on the highway at high speeds. I would get a loud clunk
sound....the kind that makes you pull over to see what fell off the
truck. I did the same thing as you. I put the truck in neutral with
it set to 4x2 mode and laying in front of it rolled it forward and
back to see if the drive shafts were turning. The passenger side
driveshaft was not turning while the driver side was. I then noticed
that there was a vacuum hose from the passenger wheel to a solenoid
but the driver side hose was hanging loose.

My first thought was that I had pulled it off while driving offroad.
Then I noticed the nice red cap over the hub vacuum inlet. When I
pulled it off, the barbed connector was shiny new and had obviously
never been connected from the factory. With the vacuum hose dangling
it had sucked up all kinds of gunk and the solenoid was shot. I
bought a new solenoid valve and once replaced and the hose properly
connected, the 4x4 system worked great.

I would advise you to trace all of the vacuum hoses and if anything is
loose or unplugged then you probably have debris in the line. Manual
hubs would be a great addition. While there is a bit more maintenance
for them (repacking), they are reliable and I had them on an old
Bronco II and they always worked. You just have to have the foresight
to lock them before getting into any muck or you better have some good
boots.

OzarkMtbr
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