For him to feel the hop, both the transfer case and at least one hub need to be not disengaging. The assumption was that the t-case was not disengaging, or at least not immediately. Even with one hub disengaged, assuming the t-case it still engaged, the front diff cannot act as totally open, because it is still being turned at exactly the same speed as the rear diff...one wheel disengaged will not make up the difference because the other locked wheel is still spinning the spider gears at the rate it is turning on its own in the corner, which is different (especially on a sharp turn) than the rear wheels. It is not the same scenario as a front or rear drive vehicle, because in this case even though the front wheels are not pulling, the diff is still being turned by the front driveshaft, and the one locked wheel is being turned by friction on the road, but at a different speed than the driveshaft is turning the spider gears. Note that if both front hubs disengage but the transfer case does not, it will still drive and turn normally. It seems odd that both the transfer case and at least one hub are acting up on a truck so new.

As for your issue with this type of system, ordering the manual hubs / manual t-case shifter solves the problem. Or even converting your automatic hubs to manual Warn hubs should solve 99% of the problems. I like the system for its relative simplicity. I do understand your concern with being locked out of 4x4 if a problem occurs.

 

Good point. BCM, one (or both) of your automatic hubs are not manually moved to the lock position, right? They are in "auto?"

 

Just checked... Both are on auto. If they were set to manual, or at least one of them, wouldn't I feel it without switching to 4x4?

 

No, I don't think you would, assuming you were not in 4x4 and the transfer case was actually disengaged. At most you might hear a bit of extra noise, but basically the action of the differential would just spin the other unlocked half shaft and the driveshaft.

You would notice in 4x4 that basically you would gain no extra traction.

 

Feel the hop? One in manual or both? No hop without switching the t-case to 4wd with both locked.

 

Ah, but this is not true Troverman, think for a second. If one hub is not engaged on the front end then the power provided by the transfer case (at exactly the same speed as the the power delivered to the rear axle just like you said) through the front driveshaft, pinion then crown to the differential carrier, through the spider gears to guess where , exactly the path of least resistance... The unlocked axle, it is free to turn at whatever speed required to take up universal joint irregularities, differences in speed front to rear, slippage whatever, the driver won't feel a thing except he/she is still driving in only two wheel drive. This scenario is easier on the front diff then just one hub locked in and the other hub and transfer case unlocked. There is no such thing as three wheel drive with these trucks.

 

Maybe you are correct, it's hard to visualize. I agree, no such thing as 3WD...we are not worried about the transfer case "providing" front drive, as you are correct, it will not...it will flow to the unlocked hub and just spin the half-shaft. The thing is, with the transfer case engaged, we are now powering the front and rear diffs at the same speed. The rear end is causing the truck to move forward; the front end is spinning the unlocked half shaft. But because the truck is moving, we are also spinning the locked half shaft at a different speed, as the truck turns. Maybe all the speed differential is eaten up by the unlocked half-shaft...but in my mind, we have 3 different speeds to deal with, and a diff can only deal with two. One is the front driveshaft speed, one is the locked half shaft speed, and one is the forward movement of the whole truck.

 

Yes you will move forward but if the front wheels encounter any resistance say a curb or snow the power will follow path of least resistance and put the power straight through the unlocked half shaft making the truck effectively 2wd

So yes the truck will move with 3wd but it is essentially a less efficient and fuel
consuming 2wd as far as traction is concerned.

Sent from my Galaxy using IB AutoGroup

 

When the truck is in 4wd with one axle locked it will be in 2wd and the locked front axle will just be going along for the ride at the same speed as the rear axles and the unlocked one will be spinning at the same speed also. All 4 axles will be spinning at the same speed but only 2 are pulling.
If you switch the T-case to 2wd then the locked front axle will be spinning at the rear axle speed while the unlocked one will be spinning in reverse at the same speed as the locked one, (but backwards).