Dyna Storm: Diff Issue

[Origineelreclamebord 45]

Hi everyone,

I'm in the process of rebuilding my Dyna Storm diff. I've just rebuilt it - exactly as per manual, but there is a slight problem. The diff doesn't feel very grainy, which of course is good, but throughout the rotation of the diff it becomes looser and tighter (in a smooth fashion, not notchy). It's only one spot in the rotation.

My first thought was 'the balls are deformed.' The balls have been in the diff for 3 or so years now, but I don't drive the car a lot, and the balls in the diff are tungsten carbide, so I'm not sure you'd be able to deform these like steel balls. The thrust bearing looks smooth, the disk springs don't look damaged, and though the pressure plates have grooves there was no sign of damage on them (and grooves appear pretty quickly in use).

Are there any suggestions what I could look at before trying loads of new parts?

[kontemax 1725]

Mine on my Dyna Storm do the same. On my Dyna Blaster do the same too. I think it's a characteristic of the Dyna Ball Diff and I remember the same on the Astute or other ball diffs.

Max

[Origineelreclamebord 45]

Lol, ok I never noticed it before when I was rebuilding the Dyna diff, that's why I found it a bit strange. Anyway, I rebuilt the car now and I'll just test it then. I moved back to what should be the kit setup, what I remember from it the setup was very nice for soft dirt and bumpy surfaces - exactly what I'll be running on next weekend in a vintage race!

Thanks for your advice/comment

[kontemax 1725]

Max

[redzone 212]

I just rebuilt mine with new parts and it feels smooth/uniform, you could try flipping the pressure plates so the groove is on the opposite side?

[94eg! 834]

I was gonna say try flipping the pressure plates, except for a different reason...

I noticed the pressure plates on my old Vanquish ball diffs were cut out on a stamping machine. The same could be true for the DS. This process leaves the cut edges of the plates with rounded-off edges on one face only. If I assembled the diff with the rounded edges facing toward the balls, the diff would be very inconsistent. After flipping the plates around so the sharper square-edges faced toward the balls, the diff was much better. Not perfect, but much better.

Also try sanding the plates.