Subj: Re: [ZR2] 4x4/Defroster problem
Date: 9/28/99 6:00:01 PM Central Daylight Time
From: djplonka@ix.netcom.com (Don Plonka)
Reply-to: zr2@palmtop.net
To: zr2@palmtop.net

Find the place on top of your transfer case where the vacuum lines connect.
This is the top of the vacuum switch. Just pull the vacuum lines off (all three
stay connected to each other & they can only go back on one way). The switch
has a large hex (7/8" I think???) and unscrews from the case. Make sure you
clean the area around the switch as well as possible before you unscrew it. You
will have to do this mostly by feel, you can't see anything. The switch has a
plunger that sticks down into the case, if the plunger doesn't move freely,
this might be your problem. It's cheap to replace so it's worth taking a look
at.

Patrick Cassidy wrote:

> I know that our 4x4 works off a solenoid, but, maybe someone can explain
> this to me, and a possible remedy. My truck performs pretty well, in 2wd
> on the road, unless I turn on the defroster, then after about a mile or so,
> the front hubs "kinda" engage, the wheels don't turn, but the hubs engage
> enough to make a kinda buzzing sound. If I turn off the defrost, and
> engage the 4x4, then back to 2 Hi, it usually quits, and is ok.
>
> Also, and this might be related, or not. When I put the 4hi in, and then
> go back to 2 hi, the front won't disengage for a while, then it does, with
> a big "clunk".
>
> I was thinking possibly a vaccuum leak? That is the only link from the
> defroster to the 4x4 that I could imagine....
>
> Any ideas? I'd like to get it fixed before the snow starts flying!
>
> Thanks all.
>
> POC
> Patrick Cassidy
> '96 GMC Highrider
> '57 IHC A-140 4x4