Vibration with Gear Vendors installation

[Bad News]

02 LWB 7.3 w/ 4R100. Installed Gear Vendors a while ago, have been unable to get rid of a drivline vibration that starts a 72MPH. Had the first shaft shop rebalance the shafts twice, remake the front shaft once. 2nd driveline shop rebalance( and they claimed there were issues w/ first balance). Also have tried just about every combination of angles, moving the center bearing up down and trans up and down. GV claims it is in the shaft balance but at this point with 2 totally different shops balancing I don;t think so.
As I remember when I hook the trailler to the truck the vibration lessens although it is still present. That tells me that changing the rear shaft angle has an affect.
Any suggestions?

 

[kip4234]

2 wheel drive?????? You dont have any cross-member or bracing on the gear vendor at all do you????? they should not have any. I have had one forever and it is vibration free. I did have to change my pinion angle on the rear end as it changed with the added length of the gear vendor.

 

[bad12jr]

Sounds like a pinion angle problem. With the load it gets better leads to it even more.

 

[Bad News]

yes 2 wd. Lwb so it has 2 shafts and a center bearing , which i also changed already.

 

[CGMKCM]

Just offering this up, maybe a one piece drive shaft would give you better angles? Google Gear Vendors one piece drive shaft, might find some information that would help.