Retrofit selectable 4x4 on fulltime 4x4

[Schwaltzbauer]

Hi everyone,
as I mentioned in the presentation thread I'm currently looking for a 2000/2006 Tahoe or Yukon or, why not, a Suburban.
Space on board is never enough ;-)
Not many of them can be found in good conditions here in Europe, but still I'm hopeful.

I found this 2004 6.0 Yukon Denali in Poland, excellent internal and external conditions, mechanics looks really good too, but it has the automatic fulltime 4x4 drive train....

Now, as someone who always loved and practiced offroading I've always owned and preferred 4x4 vehicles almost always with manual 4x4 selection.
With or without center diff, but still almost always with manual 4x4 selection.
This allows also some fuel saving on long highway trips or in standard asphalt driving, when the front traction isn't needed.

Long story short, my question is does anyone know if it would be possible to transform this Yukon Denali automatic 4x4 drivetrain into a "standard" Tahoe/Suburban/Yukon button selectable drivetrain?

Thank you all!!

 

[S33k3r]

With enough money and time, yes. It is unclear if it is feasible or not. Your going to need a transfer case control module, an encoder motor, push buttons for the auto 4WD, and likely accomodations on the transfer case for the motor.

Now, for this generation of vehicles, some of the 2500HD trucks actually had manual 4WD; it was a lever in the cab that went through the floor to allow the driver to make the changes. This system might be more feasible for your needs.

Those things said, I have exhausted my knowledge on the topic of a conversion.

However, I would advise against the conversion. The only two things you lose with AWD vs 4WD are 1) 4WD lo and 2) About 1 mile per gallon (I don't know what the liter conversion is). The GM AWD setup is really good, especially for a street truck that only spends some time in bad driving conditions. I placed my youngest daughter in a Sierra Denali with AWD for that reason. I researched that a LOT.

In the end, it is your rig, so I look forward to you customizing it in a way that you enjoy and sharing those changes with us. Sometimes it is really fun when I am wrong.

 

[rockola1971]

Hi everyone,
as I mentioned in the presentation thread I'm currently looking for a 2000/2006 Tahoe or Yukon or, why not, a Suburban.
Space on board is never enough ;-)
Not many of them can be found in good conditions here in Europe, but still I'm hopeful.

I found this 2004 6.0 Yukon Denali in Poland, excellent internal and external conditions, mechanics looks really good too, but it has the automatic fulltime 4x4 drive train....

Now, as someone who always loved and practiced offroading I've always owned and preferred 4x4 vehicles almost always with manual 4x4 selection.
With or without center diff, but still almost always with manual 4x4 selection.
This allows also some fuel saving on long highway trips or in standard asphalt driving, when the front traction isn't needed.

Long story short, my question is does anyone know if it would be possible to transform this Yukon Denali automatic 4x4 drivetrain into a "standard" Tahoe/Suburban/Yukon button selectable drivetrain?

Thank you all!!

You are not using the correct term for the transfer case that would be in a Denali. It would be a AWD(All Wheel Drive)....not Automatic Fulltime 4x4. The regular yukon, tahoe, etc could have a selectable 2/4hi/4lo or 2/4hi/4lo/Auto 4WD and the "Auto 4wd" is not the same as AWD. An AWD unit is in 4wd all the time indeed BUT it is designed to be driven on dry pavement unlike a standard 4wd unit which bunny hop in turns on dry pavement. Auto 4WD is a 4wd transfer case that has clutches and sensors that keeps the Tcase in 2wd until the system detects wheel slippage (loss of traction) and then the clutches immediately react and you are then in 4wd. Once slippage stops and is detected as such then the clutches react and disengage the 4wd automatically.

Sure the mod can be done from AWD to Selectable 4wd (NP246E Tcase) but it wont be cheap and will be a substantial amount of work. The front output side of diff is different, the driveshaft on rear I believe is different, maybe even the front driveshaft too. The Electronics and sensors are different so wiring harnesses will be different and of course the Tcase will be different. New Process 246E vs Borg Warner BWXXXX unit.

Doesnt sound like a fun project at all. The BW unit doesnt eat up that much extra gas anyway. I own a 05 Yukon Denali AWD and its not that bad at all vs my Tahoes with 5.3L and NP246E Auto4WD Tcases.

 

[Schwaltzbauer]

Thank you guys for your words!

I was thinking about this because the car I've been driving since 2015 and we use for long trips through Europe has a very similar all-wheel drive system, which is indeed very valid, but it has some flaws.

It is certainly less ready than a mechanical differential that is always gripping, like Audi's Torsen, it always has a minimum of lag, and when going downhill on low-grip surfaces you can't get the benefit of grip even in the rear because it remains disconnected.

These are flaws that I feel because I am used to using a certain type of car on unconventional terrain, most drivers would not even realize.

Besides, it is a car, not an off-road vehicle, so in the end it's fair that the mechanical solutions adopted are geared toward asphalt use and not dirt use.

However, then, if I understand it correctly, the AWD system in the Denali is a classic 4x4 always on grip with a center diff, which is why it can be used on asphalt without the bunny hopping and without the tendency to go straight in corners.
Whereas the Tahoe/Suburban/Yukon with manually engageable front-wheel drive and auto4WD basically have a clutch system that engages the front when needed, and the 2WD and 4WD buttons just lock this clutch engaged or disengaged, but without a center diff to "distribute" traction here's the bunny hopping if I engage 4WD on asphalt.

Right?

 

[rockola1971]

Thank you guys for your words!

I was thinking about this because the car I've been driving since 2015 and we use for long trips through Europe has a very similar all-wheel drive system, which is indeed very valid, but it has some flaws.

It is certainly less ready than a mechanical differential that is always gripping, like Audi's Torsen, it always has a minimum of lag, and when going downhill on low-grip surfaces you can't get the benefit of grip even in the rear because it remains disconnected.

These are flaws that I feel because I am used to using a certain type of car on unconventional terrain, most drivers would not even realize.

Besides, it is a car, not an off-road vehicle, so in the end it's fair that the mechanical solutions adopted are geared toward asphalt use and not dirt use.

However, then, if I understand it correctly, the AWD system in the Denali is a classic 4x4 always on grip with a center diff, which is why it can be used on asphalt without the bunny hopping and without the tendency to go straight in corners.
Whereas the Tahoe/Suburban/Yukon with manually engageable front-wheel drive and auto4WD basically have a clutch system that engages the front when needed, and the 2WD and 4WD buttons just lock this clutch engaged or disengaged, but without a center diff to "distribute" traction here's the bunny hopping if I engage 4WD on asphalt.

Right?

Yes. Except the Tahue/Sub/Yuk have manually engageable 4wd not front wheel drive. Some have the auto4wd feature, especially the LT,SLT models. Both of my 2003 Tahoe LT's have the Auto4WD button.

 

[Mudsport96]

You could get a manual 241 transfer case and get around all of the electronic crap. But you will most likely need to get different driveshafts. But i do not kjow for sure