Finished my T-56 swap and everything shifts smooth but I'm getting some rattle noises or marbles sound when under heavy load starting in 4th gear . When I'm in 5th I can cruise smoothly but if I apply anything more than light throttle it will start to make this awful rattle marbles sound until I let off . Been reading up on the subject and wondering if maybe my timing is too advanced. I do have some really light springs in my H.E.I.. and pretty sure my timing might be a bit off but it runs pretty good. Was thinking maybe T.O.B. but sounds more like pinging not sure though.