Still does it after checking pressures. Does it in 3rd, 4th, 5th, 6th regardless of revs, from between 50/55 and arround 70 (btw, 70 in 3rd sounds awesome).
Thing is, only occurs for 5 minutes is, first 15 minutes after coolant gauge shows normal/middle it is fine. 4th and 5th both cleanly pull 50. No vibration. Then suddenly it comes on, doesn't matter whether the road is straight, veering right or left, it just does it. Then, it just goes off.
The brake is still binding though, because it will hold on a slight slope in either direction out of gear with no handbrake.