TF727 third gear vibration

[GoDartGo]

I have a TF727 that starts to vibrate at around 3,000 RPM, but only in drive (3rd gear)
no vibration in neutral.
Any thoughts?

 

[philcollins]

Driveshaft or Wheel imbalance. Could be a worn U joint.

 

[DusTed74]

Could also be the tail shaft bushing.

Ted

 

[AJ/FormS]

Put the rear end on jackstands. Remove the wheels and drums. Start her up and run her up into the vibration zone. Still there? Most likely it is the driveshaft or related components. But before you rush out and get it rebuilt you need to think about when and how this vibration first started, I might just be a bad pinion angle.

 

[GoDartGo]

pinion angle is out, nothing has changed in the last 6 years and it just started last summer before I put it up.