When I discovered the IDS (isolated drive system) I began to think that it had to be the cause.
Problem or wierd thing:
With clutch in and rear brake applied at about 40 MPH, I feel a vibration from the rear tire that feels like going over speed stripes as you approach a rural stoplight or the wakeup stripes along the edge of the interstate. The vibes are not quite as strong as the examples.
If the IDS is the source, I can't explain how.