[AT] OT - Chevy Autotrac transmission question

[badams at tractors.bloomington.in.us]

Steve,
 	It's a 1998 Tahoe.  I Think this was the first offering of 
AutoTrac.  If the clutches are shot is it just 2WD with extra stuff 
spinning?
 	I was hoping for a 4WD ride through the winter that could pull 
my trailer if needed while my '86 slant six Dodge gets it's 200,000 mile 
Re...  For those of you who know the truck that doesn't include paint:)
 	I've avoided 4WD for 20 years because it seemed silly to move all 
that stuff 15K miles a year to use it for 10-20 miles rather than wait a 
day for the snow plow.  Our schedules and commitments have changed to the 
point where I'm willing to tyr it.
 	Thanks again for your help.
Brice

On Sun, 4 Dec 2005, Steve W. wrote:

> Brice,
>  Of all the GM 4X4s the auto 4 is about the worst for reliability. They
> use an electronic clutch pack to shift the front end in/out of gear and
> they have a nasty habit of burning up those clutches. IF this is a 2002
> truck the switch unit should light up under whatever mode the T-Case is
> in at the time and stay lit. If it is not doing this then either the
> module is bad OR the fuse for it is blown. The fuse would be a good
> thing because that switch module is about 200.00 dollars for a
> replacement. It is POSSIBLE to repair some of them if the problem is
> that you have bad solder joints in the switch (also a common problem
> with a couple versions of the module) You just take it apart and reheat
> the solder on the pins that connect the cable harness. If this is a 2003
> and up those have a switch that can lose it's programming and default to
> off status until it gets reprogrammed (40-50 bucks at a dealer).  The
> auto system works great when it works correctly, the problem usually is
> if you drive it on wet roads in 4Auto. The auto system uses the same
> sensors as the ABS to tell if your losing traction, on wet roads the
> unit will cycle on/off a bunch because of the water causing minor
> differences in wheel speed. This wears the clutch pack and causes you to
> lose 4x4.  If this is a GM dealer They should know this problem REALLY
> well. There are a couple of TSBs on it. If they are not GM then ask to
> take it to a GM dealer and have it checked out BEFORE you agree to
> anything. There is real money in that front differential if it is bad.
> Same with the switch in the dash. Figure 1000.00 if the front end has to
> be rebuilt.
>
> Steve Williams
> Near Cooperstown, New York
>
>
> ----- Original Message -----
> From: <badams at tractors.bloomington.in.us>
> To: "Antique tractor email discussion group"
> <at at lists.antique-tractor.com>
> Sent: Saturday, December 03, 2005 8:50 PM
> Subject: [AT] OT - Chevy Autotrac transmission question
>
>
>> I'm looking at a Chevy 4WD to pull a trailer with a tractor on it.
>> There are 4 buttons on the dash that seem to select 2High, 4High,
> 4Low,
>> and 4Auto.  There seem to be LEDs in the switches but none of them
> stay
>> lit.  I think the switches perform the proper operations but the LEDs
> just
>> light for a couple of seconds then go out.  The dealer involved is no
> help
>> so I'd like to here from someone who owns one.
>>
>> Thanks,
>> Brice
>>
>> _______________________________________________
>> AT mailing list
>> Remembering Our Friend Cecil Monson 11-4-2005
>> http://www.antique-tractor.com/mailman/listinfo/at
>>
>