Thermal Actuator - How Does it Work?

[Steve Gerland]

The part in question is the 'thermal actuator' on the front
differential of a 1993 Chevy 4X4. I'm just curious what
makes it work. Is it some sort of thermally expanding
fluid with a heater?

Steve

"59" is spam blocker.

[William Kenning]

yep, that's exactly what it is.. except it's actually a gas not a
liquid. when the heater expands the gas enough a rubber balloon pushes
on a rod to engage the front axle. Depending on your vehicle, you may
be able to upgrade to the new fast actuator being used on the 97 and
newer GM trucks. it works using an electric motor and won't disengage
under cold weather or when the key is turned off like the old thermal
actuator.

Steve Gerland wrote:

--

Bill Kenning
ICQ# 8426306
AOL IM: Bigdodg
'83 Dodge Stepside 4X4
'79 Dodge Rustbox 4X4
'98 Chevy S-10

There is only one ultimate off road machine.
The one you build with your own hands.

[Steve Gerland]

Thanks for the quick response. Now the only thing I can't
figure out is whatever posessed the GM engineers to use
such a weird contraption in the first place.

Steve

William Kenning <bi...@mail.dailypost.com> wrote:
: yep, that's exactly what it is.. except it's actually a gas not a

[Bob Elfstrom]

Even as we speak, my 93 Suburban is getting the new actuator installed
at the dealer (old one died). Called and said the parts were about
$100 and an hour or so labor. Comes in a kit with new wiring harness,
designed to retro-fitted on older models.

Take Care,
Elf

[William Kenning]

only one reason. It was CHEAP!!! the only reason we now have the fast
actuator is because of the Auto-trac system used on the new Suburban and
Tahoes.

Steve Gerland wrote:

> Thanks for the quick response. Now the only thing I can't
> figure out is whatever posessed the GM engineers to use
> such a weird contraption in the first place.
>
> Steve

> --