W124 Drivetrain vibration since rebuild

[ps2cho]

Hi guys,

I finished rebuilding my 300TE's rear end.
I did:
Subframe and differential mounts
Lower control arm bushing and carrier arm bushing
All 3 control arm links and tie rods
New GKN axle half shafts both sides
Differential axle seals
Propshaft flex disks front and rear, bearing and rubber support

Got it aligned after.

It drives perfect on the streets but on the freeway it has a little vibration felt at 70mph and over. Less than 60 and its not there.

No vibration before doing this work.

**when I removed the prop shaft, it was not aligned with the MB notches so I assumed the PO could have put it back on wrong, so I put it in line with the MB notches. Could it simply be this? I have no way of knowing the old position now of course.

Where should I look or anything to test?

Thanks