Thread: Prop shaft phasing

Background: I have done a heap of work on my 2008 'Puma' 130 and am now chasing a rumbling noise on coasting; no noise on drive or over-run but a constant rumble when coasting; shows up during gear changes and can be reproduced by using Mexican Overdrive (neutral) downhill. The noise seems to come from the rear. I altered the phasing of the rear propshaft which got rid of the rumbling noise- which suggests I was on the right track- but I then had a vibration at around 95-100km/hr. Put the shaft back how it was and the rumble is back- which again suggests I'm on the right track but not quite at the destination. The sliding joint in the shaft has only five possible alignments as it has ball grooves rather than simple splines, so alignment can only be altered in increments of 72 degrees. The propshaft was not disassembled during the work but the suspension is now higher and the rear diff pinion probably points upward a few degrees more. The yokes are at 45 degrees out-of-phase, can't recall whether the gearbox end leads or trails the pinion end.

Looking into this a few weeks ago I came across a chart which showed the proper amount of 'out-of-phase' depending on the angular difference between the gearbox shaft and the diff pinion shaft. I can't find the chart now and wondering if anyone is able to provide this info or direct me to a source. Trial and error is getting to be time consuming and I'm sure there's actually a science to it.

I pulled the shaft out again this morning (took it for a quick drive without the rear propshaft to again confirm it as the likely source of the noise- no noise without it) and separated the two hales, closer inspection reveals that although there are 5 rows of balls, there are 10 sets of grooves- so increments of 36 degrees are possible. I seem to have found the sweet spot- touch wood- by rotating one position forward of where it started.