So went by Clutch repair, guy said grinding was the transmission. As it was still grinding in 1st and 2nd gears (intermittently, you would kind of have to rev up engine, and depress clutch in 1st or 2nd, for the sound / vibration appear).
So, second stop on way home, found transmission place that was open. He seemed to think its the Slave cylinder causing this, as there would be grinding sounds from the truck, WHILE DRIVING, not sitting parked.
Am going to drop off truck at 2nd place tomorrow, and they will get a closer look at it and make proper diagnosis. There was plenty of fluid in the master cylinder, but maybe the slave is bad (it went out 1.4 years ago, and replace it and the clutch).
If anyone else has any input, would appreciate it.