2001 Tahoe 4wd theory

[2015TahoePPV]

I’m looking at using a 2001 Tahoe as the basis for a project. Does anyone know off the top of their heads what happens when you push the “4wd” button?

I used to have a 2002, but I don’t recall if it had a BCM or any other annoying computers like the newer ones do. What I’m trying to do eventually is transfer a classic truck body onto this chassis, keep the drivetrain with a neutered wiring harness and minimal computer controls. I’m going to ditch ABS, traction control, etc.

Thanks for any help, this is going to be a big project.

Ed

 

[Marky Dissod]

Do you mean the 'Auto 4WD' button, or the '4Hi' button?

'Auto 4WD' waits for brief rear wheel slip before temporarily engaging the front wheels.
Once it thinks everything is ok, it puts the front wheels back on standby.
In theory, you could stay in RWD so long as road conditions are good.

'4Hi' is permanent 4wheel drive.
Avoid use unless traction is less than ideal - raining badly or worse.

 

[2015TahoePPV]

I’m wanting to be able to select 4Hi or 4LO and have the system work as designed. I think “auto” would rely on the ABS computer, which I wasn’t planning to keep. I messaged Painless wiring also.

 

[Doubeleive]

I’m looking at using a 2001 Tahoe as the basis for a project. Does anyone know off the top of their heads what happens when you push the “4wd” button?

I used to have a 2002, but I don’t recall if it had a BCM or any other annoying computers like the newer ones do. What I’m trying to do eventually is transfer a classic truck body onto this chassis, keep the drivetrain with a neutered wiring harness and minimal computer controls. I’m going to ditch ABS, traction control, etc.

Thanks for any help, this is going to be a big project.

Ed

should be no auto and no traction control on a 2001, there would only be abs. in other words no nannies except abs

 

[2015TahoePPV]

Is there anything that happens with the front hubs/ differential? I’m wondering what “tells” the transfer case and front axle to lock everything in 4wd.

 

[Marky Dissod]

I think 'auto' would rely on the ABS computer, which I wasn’t planning to keep.

No clue whether or not an ABS control module is needed to properly use 'Auto 4WD'.
I'd be pleasantly surprised to find that an ABS computer is not needed for 'Auto 4WD'

 

[afpj]

My 2002 has no traction control, and abs is not involved in the auto 4wd operation. It's purely mechanical based on the np246 transfer case's clutches.

 

[DirtDigler]

should be no auto and no traction control on a 2001, there would only be abs. in other words no nannies except abs

My 2001 does have Auto but no traction control.

 

[Marky Dissod]

My '02 Tahoe Z71 does have ABS, and Auto 4WD, but no Traction Control.

 

[Doubeleive]

ok, I guess some do and some do not.
some will have a switch like this (no auto) I'nm guessing it depends on the trim level.

 

[Doubeleive]

Is there anything that happens with the front hubs/ differential? I’m wondering what “tells” the transfer case and front axle to lock everything in 4wd.

the encoder motor and actuator are engaged with a switch
some of the base level pickups (old and new) have a manual hand control on the floor, like old school 4wd
never seen it on a suv though, at least not since 00

 

[Doubeleive]

 

[Marky Dissod]

Doubelieve shows a switch panel with 3 buttons. Mine has a 4th round button 'Auto 4WD' on top.
I do not know what trim options corresponded to Z71 in '02

 

[Fless]

For the AUTO TC system there should be a Transfer Case Control Module (TCCM or ATCM) under the dash. The dash switch is connected to that.

 

[2015TahoePPV]

Thanks for the input everyone. My son and I are dropping a K5 Blazer body onto a 2000-2006 Tahoe chassis. I’m going back and forth between customizing the heck out of the wiring and ancillary systems, or just using all of the Tahoe wiring/ components and going with a custom “retro” type dash. There’s no real downside to keeping the ABS, etc, I suppose.

 

[2015TahoePPV]

My 2002 has no traction control, and abs is not involved in the auto 4wd operation. It's purely mechanical based on the np246 transfer case's clutches.

Interesting. That would be the easiest solution. Is there anything going on at the front axle as far as engaging the “hubs” or does it all happen at the transfer case?

 

[Doubeleive]

Interesting. That would be the easiest solution. Is there anything going on at the front axle as far as engaging the “hubs” or does it all happen at the transfer case?

transfer case/front diff does it all on this gen

 

[2015TahoePPV]

Is there a servo/ actuator of some sort on the front diff? Assuming it gets power from the transfer case?

 

[Fless]

Yes, there's an actuator on the front diff. Command comes from the TCCM, not the transfer case.

 

[V327839]

Also, I believe the auto feature works through the three speed sensors on the tcase as well. Not totally sure, but my 04 sub z71 has them and auto 4wd and I know that push button 4wd operation requires them all to be working properly. Just trying to help.