OK, you have accomplished a lot, even if it does not seem like it.
Now we can be fairly sure that it is not a front steering shimmy, a out of balance tire
or bad rim, or broken motor mount.
I suspect that the ultimate problem is going to be driveshaft angle, but I think there is a related problem right now.
When you raise a vehicle to give the clearance to put on bigger tires and thereby more ground clearance, the drive shafts have to point farther down.
U-joints have a maximum amount of flex back and forth that they like. When you exceed that, bad things start happening.
When you exceed it a lot, the driveshaft U-joints have to go from bent a long way one way to bent the same amount the other way, and this sets up a bad vibration.
But, if your driveshaft is right on the limit, it won't vibrate all that much, but since the joints are shifting fast and far, they wear out fast.
Right off the top of my head, I do not know of any way to stop a driveshaft out of limits from vibrating temporarily. Once you go too far, that shaft is going to vibrate until you correct the angle.
In your case, it does not seem to have vibrated at first.
I think that you have a bad U-Joint, probably brought on by the excessive angle.
I would take one end or the other of the driveshaft off, and try to flex all the joints.
Better to take both ends off, but I am lazy. I bet you are going to find one that is binding and is hard to flex.
This would cause the vibration.
To double check, you SHOULD be able to remove the rear driveshaft, Lock the front hubs, and put the transfer case into HiLoc, and drive off.
If its the rear shaft, the vibration should be gone.
Driving in HiLoc on dry hard surfaced roads should be fine with the rear driveshaft removed.
I remember you were asking about the different gear settings. If you understand how a differential works, and why its necessary, which I assume you do because you have worked on cars before, I will type up a reasonably brief account of 4WD, and what you need to know to operate it, later on tomorrow.
J.
Now we can be fairly sure that it is not a front steering shimmy, a out of balance tire
or bad rim, or broken motor mount.
I suspect that the ultimate problem is going to be driveshaft angle, but I think there is a related problem right now.
When you raise a vehicle to give the clearance to put on bigger tires and thereby more ground clearance, the drive shafts have to point farther down.
U-joints have a maximum amount of flex back and forth that they like. When you exceed that, bad things start happening.
When you exceed it a lot, the driveshaft U-joints have to go from bent a long way one way to bent the same amount the other way, and this sets up a bad vibration.
But, if your driveshaft is right on the limit, it won't vibrate all that much, but since the joints are shifting fast and far, they wear out fast.
Right off the top of my head, I do not know of any way to stop a driveshaft out of limits from vibrating temporarily. Once you go too far, that shaft is going to vibrate until you correct the angle.
In your case, it does not seem to have vibrated at first.
I think that you have a bad U-Joint, probably brought on by the excessive angle.
I would take one end or the other of the driveshaft off, and try to flex all the joints.
Better to take both ends off, but I am lazy. I bet you are going to find one that is binding and is hard to flex.
This would cause the vibration.
To double check, you SHOULD be able to remove the rear driveshaft, Lock the front hubs, and put the transfer case into HiLoc, and drive off.
If its the rear shaft, the vibration should be gone.
Driving in HiLoc on dry hard surfaced roads should be fine with the rear driveshaft removed.
I remember you were asking about the different gear settings. If you understand how a differential works, and why its necessary, which I assume you do because you have worked on cars before, I will type up a reasonably brief account of 4WD, and what you need to know to operate it, later on tomorrow.
J.
