Describe to me how the 2-speed transfer case works... 2011 Tahoe 5.3

[hillstrubl]

Coming from the jeep and Land Rover worlds, I understand their transfer case offerings well... School me on what's in my 2011 Tahoe (5.3, rear locking diff). Auto obviously engages the front diff but on the transfer case side, is it just an open center diff? Viscous coupling? Clutched center diff? How does it know when/how much power to send to the front?

I get 4Hi, N, 4Lo settings + locked center diff modes. Its the auto setting that I'm asking about.

- follow up question, as I have the rear locking diff, what type is it? limited slip, clutched? geared? Does it actually lock-lock if given the conditions to do so? I've heard chirps when going around turns in slippery conditions in 2wd previously, just wondering what triggers it and if its tied into traction control at all.

 

[Ibustbravo]

The best info will be from alldata.com.. It's a $20mo subscription.

 

[wjburken]

When are in Auto4WD, your vehicle will engage the front wheels, just as in 4HI, as needed, based on what the wheel speed sensors are reading. If they sense wheel slippage, it will engage the front wheels and then disengage when everything is back to normal. There is no varied splitting of torque.

 

[Fless]

Should be the NQH TC. Take a look at this post and the embedded thread to see if it's what you're looking for:

Auto mode turns on 4x4 mode

I found this nugget... Great info, but are you sure that the 246 is for GMT900s? Everything I'm seeing is that it's for older, pre-2006/7 vehicles. Based on some digging, (and my RPO sheet) I have the NQH MP3023/3024: https://evopower.ca/mrws/filedriver/MP_Transfer_Cases.pdf

www.tahoeyukonforum.com

 

[j91z28d1]

I had not seen that. good stuff.

The Magna Powertrain MP3023/3024 NQH - Transmission Digest

Learn about Magna Powertrain's MP3023/3024 NQH transfer case: active and electronic, clutch application, shift positions, and model variations.

www.transmissiondigest.com

 

[swathdiver]

Coming from the jeep and Land Rover worlds, I understand their transfer case offerings well... School me on what's in my 2011 Tahoe (5.3, rear locking diff). Auto obviously engages the front diff but on the transfer case side, is it just an open center diff? Viscous coupling? Clutched center diff? How does it know when/how much power to send to the front?

I get 4Hi, N, 4Lo settings + locked center diff modes. Its the auto setting that I'm asking about.

- follow up question, as I have the rear locking diff, what type is it? limited slip, clutched? geared? Does it actually lock-lock if given the conditions to do so? I've heard chirps when going around turns in slippery conditions in 2wd previously, just wondering what triggers it and if its tied into traction control at all.

I forget which models, a lot of Jeep offerings also use the same Magna Power transfer cases.

 

[hillstrubl]

Should be the NQH TC. Take a look at this post and the embedded thread to see if it's what you're looking for:

Auto mode turns on 4x4 mode

I found this nugget... Great info, but are you sure that the 246 is for GMT900s? Everything I'm seeing is that it's for older, pre-2006/7 vehicles. Based on some digging, (and my RPO sheet) I have the NQH MP3023/3024: https://evopower.ca/mrws/filedriver/MP_Transfer_Cases.pdf

www.tahoeyukonforum.com

The internal clutch application in the A4WD position is controlled by the transfer-case shift-control module (TCSCM), which sends a pulse-width-modulated signal in response to input from the wheel-speed sensors. The actuator motor turns a gear-driven actuator shaft, moving a clutch-application cam to engage the clutch and send torque to the front axle. When the front and rear axle speeds match, the actuator motor returns to the 5% duty cycle.

-

This sentence was what I was looking for, thank you.

I assume these clutches have a service life, any idea what that is? I guess if it's spent most of its life in 2wd (or 4wd high when needed) they should be in good shape though.