I have a 99 blazer that will will switch to 4 Hi, 4 Lo and 2 Hi. But
will not go into 4 auto anymore. I replace the dash switch and still
no luck? The blazer has 104000 on it. Any ideas where to look next.
Winter is coming quickly and my transam doesnt like snow!

Thanks,

Mike

replace the front wheel actuator with the new and improved motor driven
ones.
about 100.00
john


"Archenon" <mmester (AT) msn (DOT) com> wrote

"johnny" <ajeeperman (AT) comcast (DOT) net> wrote


I will look into the actuator. I noticed yesterday that it did
actually go into 4 auto, but today it is not working again. Could
this still be the actuator?

thanks,

Mike

Archenon wrote:

I think John is mistakenly thinking about the full size trucks.
The actuator on the Blazers is a vacuum actuator that "pulls"
the diff into engagement, the full size trucks use an electric
actuator that "pushes" the diff into engagement. There was
a change up to the actuator for the full size, but nothing that
I know of for the Blazer style of actuator. If you are getting
4lo, 4hi, and 2hi, but not 4hi-auto....I'd be looking somewhere
else other then the front diff. Are you truly getting all 4 wheels
turning when in 4hi?

Ian

The truck goes into 4 hi when you hit the auto switch. It definitely is in
4x4 when it is in 4 hi.

mmester (AT) msn (DOT) com wrote:

So you are saying that your complaint is that the light does
not come on in the auto4hi position?

Ian

It is my understanding that 4Hi and 4 Auto are two different modes. During
the last 4 years of ownership I have used both quite a bit and 4hi feels
much different then 4auto. I dont know the details of the difference. But
when I hit 4 Auto now it goes into 4 Hi and feels like 4 Hi has always felt.