4wd Engagement Time - Autotrac?

Gozer · November 29, 2008

Truck is 2007 NBS GMC Sierra with 6.0L motor and 15k miles.

How long is "normal" for engagement into 4Hi or Auto with Autotrac transfer case? Mine took 25~30 seconds the last few times whether going into 4Hi or Auto. Going back to 2wd takes only a few seconds, and it will take another 25~30 seconds to re-engage.

This is my first Autotrac vehicle, so not sure if this is normal. My 1997 with push-botton 4wd (no autotrac) was much faster.

Thanks!

geektoad · November 29, 2008

Going from 2wd to auto in my 2008 is near instant. Turn the knob and you feel the light thunk of the transfer case right away. 25-30 seconds is definitely NOT normal.

fbachman · November 29, 2008

I agree with ^^^^

Mine's pretty quick into 4H from Auto. Haven't had it in 4L yet... waiting for nice snowy and slick road to try it.

zaac · November 29, 2008

Sounds like the encoder is going bad. Usually they last longer. Mine lasted for 100k but it seems most of them screw up sooner or later. I have a 2000 Silverado and 2 other guys I work with had 2000's also. All 3 encoders went out. When mine went out I could hear that it was really straining trying to shift the TC. They are pricey but easy to change. Aftermarket is half the price of the dealership. $700 to $350 here in Canada. Good luck.

Gozer · December 1, 2008

Thanks for the info folks. Still under warranty, so I'm calling dealer today. Want to get this taken care of before winter really kicks in.

Also going to have the trim issue on B pillar taken care of.

tbondu · November 15, 2010

I'm having this same issue on my NBS 2007 Silverado. It has never been "instant" but has definitely gotten progressively slower to engage (if it does at all). Is this an item that is covered under the 5 year/100k powertrain warranty?

Thanks in advance.

Denali_Joe · November 16, 2010

I'm having this same issue on my NBS 2007 Silverado. It has never been "instant" but has definitely gotten progressively slower to engage (if it does at all). Is this an item that is covered under the 5 year/100k powertrain warranty?

Thanks in advance.

Cannot see how this would not be covered under the powertrain warranty. take it in.

Mckenzie · November 16, 2010

2Hi to auto 4wd is almsot instantaneous

2Hi to 4Hi takes about 4-5 seconds

pistonslap · November 16, 2010

Truck is 2007 NBS GMC Sierra with 6.0L motor and 15k miles.

How long is "normal" for engagement into 4Hi or Auto with Autotrac transfer case? Mine took 25~30 seconds the last few times whether going into 4Hi or Auto. Going back to 2wd takes only a few seconds, and it will take another 25~30 seconds to re-engage.

This is my first Autotrac vehicle, so not sure if this is normal. My 1997 with push-botton 4wd (no autotrac) was much faster.

Thanks!

I have a 2000 with about 120,000 miles.Yesterday it took about 10 or more seconds.(2Hi to 4Hi )Seemed damn slow at the time.

Mckenzie · November 16, 2010

Truck is 2007 NBS GMC Sierra with 6.0L motor and 15k miles.

How long is "normal" for engagement into 4Hi or Auto with Autotrac transfer case? Mine took 25~30 seconds the last few times whether going into 4Hi or Auto. Going back to 2wd takes only a few seconds, and it will take another 25~30 seconds to re-engage.

This is my first Autotrac vehicle, so not sure if this is normal. My 1997 with push-botton 4wd (no autotrac) was much faster.

Thanks!

I have a 2000 with about 120,000 miles.Yesterday it took about 10 or more seconds.(2Hi to 4Hi )Seemed damn slow at the time.

Might wanna get that looked at,my 01 with 190K miles shifts quicker than that!

tbondu · November 18, 2010

Quick update - I took the truck to the dealer today and they just called. The "front differential actuator" was shorted and was covered under the powertrain warranty. FYI for those experiencing slow/intermittend 4WD engagement. I'm guessing the short was intermittent and was also giving me a rare "Service 4WD" message (I've only seen it twice in 3 years).

FargoZ71 · November 18, 2010

Are you spinning when you try shift into 4wd? cause if Im spinning and I hit 4Hi or Auto it wont engage until I let off the gas pedal, then it's mere seconds.