Tahoe and Yukon front diff

[Ben Solo]

Hey my front diff on my 05 tahoe started making that whining and howling noise. I took the one on my 03 Yukon n put it on.
Haven't started it yet, but about to. I noticed the diff on the yukon has a solenoid or something. I already put it on the tahoe n left the plug, un plugged. Could someone lmk if I shouldn't start it or lmk what it is.

 

[MassHoe04]

That is the front drive axle actuator.

Do you have the descriptions mixed up?
I would expect the one with the actuator to be off the Tahoe, because it is 4WD.
If Yukon was ALL Wheel Drive (AWD), I would expect that one to not have an actuator, because AWD is always engaged and there is no shifting of the transfer case.

Anyway, I think you are trying to put a 4WD transfer case into an AWD or an AWD into a 4WD truck. Either way, I don't think the parts would be compatible with each other...
Maybe somebody more experience than me will know if they are compatible, but I would think not.

 

[MassHoe04]

I just realized... maybe just a difference on type of 4WD shift??
Was one of the trucks a manual transfer shift lever, rather than electronic shift?

 

[Ben Solo]

That is the front drive axle actuator.

Do you have the descriptions mixed up?
I would expect the one with the actuator to be off the Tahoe, because it is 4WD.
If Yukon was ALL Wheel Drive (AWD), I would expect that one to not have an actuator, because AWD is always engaged and there is no shifting of the transfer case.

Anyway, I think you are trying to put a 4WD transfer case into an AWD or an AWD into a 4WD truck. Either way, I don't think the parts would be compatible with each other...
Maybe somebody more experience than me will know if they are compatible, but I would think not.

The

That is the front drive axle actuator.

Do you have the descriptions mixed up?
I would expect the one with the actuator to be off the Tahoe, because it is 4WD.
If Yukon was ALL Wheel Drive (AWD), I would expect that one to not have an actuator, because AWD is always engaged and there is no shifting of the transfer case.

Anyway, I think you are trying to put a 4WD transfer case into an AWD or an AWD into a 4WD truck. Either way, I don't think the parts would be compatible with each other...
Maybe somebody more experience than me will know if they are compatible, but I would think not.

Yeah the one with the actuator is from the yukon. The tahoe doesn't have one and it is AWD. The yukon is 4×4. So it will prolly NOT engage huh? Yeah, I've got it on and ready to test but kinda nervous. yeah, the yukon is an 03" and Tahoe's an 04. Can't really afford to have a shop tell me bs I already know or could figure out...with your guys help...but worse thing would be complete swap. In already preparing for it, tho.

 

[Ben Solo]

I just realized... maybe just a difference on type of 4WD shift??
Was one of the trucks a manual transfer shift lever, rather than electronic shift?

Maybe. I'll take a pic. They're both electronic tho.

 

[MassHoe04]

OK. I am confused now... My understanding is AWD has no levers and no electronic selector buttons, because it is always engaged (no shifting involved). AWD usually has a Traction Control On/Off button, but is always engaged.

 

[Bill 1960]

Not going to work, the AWD Tahoe does not have the circuitry to engage the front diff actuator from the Yukon.

You will just have RWD and that’s going to wipe out the AWD transfer case.

 

[Doubeleive]

even if you forced the fork in I don't think it would work because it's going to bite like it's in 4wd all the time

 

[rockola1971]

even if you forced the fork in I don't think it would work because it's going to bite like it's in 4wd all the time

Im not quite sure what you mean? A AWD front end is ALWAYS engaged so it is "4wd" mode all the time. The slippage between the front and rear ends is actuated and controlled within the AWD Tcase. This is why you can drive a AWD on dry pavement but a 4wd in 4wd mode on dry pavement turns into jerky jerk. There is no difference between a 4wd and AWD front diff other than the obvious shift motor on the 4wd unit and the related output axle tube.(they can bew swapped) Otherwise they are the same (assuming same ratio). There is also an adapter than can be installed in place of the shift motor that locks the front diff into 4wd (AWD) all the time and then it behaves as a factory installed AWD front diff as long as its driven by a AWD Tcase.

 

[Doubeleive]

Im not quite sure what you mean? A AWD front end is ALWAYS engaged so it is "4wd" mode all the time. The slippage between the front and rear ends is actuated and controlled within the AWD Tcase. This is why you can drive a AWD on dry pavement but a 4wd in 4wd mode on dry pavement turns into jerky jerk. There is no difference between a 4wd and AWD front diff other than the obvious shift motor on the 4wd unit and the related output axle tube.(they can bew swapped) Otherwise they are the same (assuming same ratio). There is also an adapter than can be installed in place of the shift motor that locks the front diff into 4wd (AWD) all the time and then it behaves as a factory installed AWD front diff as long as its driven by a AWD Tcase.

then it should work that way I wasn't 100% sure I thought maybe the gear inside was different aside from the actuator, I know the fitment is the same just wasn't sure on the difference from 4wd to awd gear

 

[rockola1971]

then it should work that way I wasn't 100% sure I thought maybe the gear inside was different aside from the actuator, I know the fitment is the same just wasn't sure on the difference from 4wd to awd gear

No difference internally once you get past the 4wd actuator and the arm that the actuator pushes against. There is an adaptor that essentially uses the actuator mounting bolts and just presses the arm in full time once installed. The 4wd actuator housing with actuator can also be installed on the AWD front diff also.

 

[MassHoe04]

Thanks for the educational and detailed explanation @rockola1971 !
I had a feeling, that the 4WD diff and the rest of the AWD would not be compatible as-is.
I learned a lot from this discussion.

So, with that adapter replacing the electric actuator to keep the front diff engaged all the time, he would be good to go (assuming gear ratios match).

See if I am understanding your notes to the OP correctly...
It is not advisable to try running the truck without that adapter (replacing the electric actuator) to keep the front diff engaged 100% of the time. Running the front diff disengaged on the AWD system would likely damage the AWD transfer case. He needs the adapter in there before trying to drive anywhere. Did I get that right?

 

[George B]

If it were me I would swap over the AWD extension housing and right side shafts and have the correct setup.
This will give you the idea. Near the end they swap that extension housing. I have had mine off before. It’s easy and you can do it with the unit in the truck. At least on my NNBS.

 

[rockola1971]

Thanks for the educational and detailed explanation @rockola1971 !
I had a feeling, that the 4WD diff and the rest of the AWD would not be compatible as-is.
I learned a lot from this discussion.

So, with that adapter replacing the electric actuator to keep the front diff engaged all the time, he would be good to go (assuming gear ratios match).

See if I am understanding your notes to the OP correctly...
It is not advisable to try running the truck without that adapter (replacing the electric actuator) to keep the front diff engaged 100% of the time. Running the front diff disengaged on the AWD system would likely damage the AWD transfer case. He needs the adapter in there before trying to drive anywhere. Did I get that right?

Yep AWD Tcase will destroy itself if not hooked up to a load. You have to have the front diff locked in and always have the front driveshaft installed.