After installing Tom woods front driveshaft I’m noticing a very slight vibe between 65-70 mph. Only thing I’ve changed is the front driveshaft to a Tom Woods one. What should I check before I start down the path of the driveshaft balance? I torqued the flange nut to specs when I reinstalled it

 

if that's all you changed then I would go straight to having the shaft balanced.

 

It’s driveshaft for sure, few years back I bought a new heavy duty driveshaft that was not cheap either ($350), and as soon as I put it on started vibrating at around 55-60 mph , pulled it and put back original & everything fine, contacted seller but they didn’t want to accept their driveshaft was not balanced.
Dont drive like that it will damage the T-cast front bearing.
Try calling seller & tell them they send you a bad/non balance driveshaft,,
Good luck.

 

Bought a new one last year. Had to return it, not balanced at all and would shimmy all over at exactly 50mph, and the excuse was that it was a 'heavier' driveshaft...

Have on older version TW , and it was a smooth as glass...really smooth...until the center ball crapped out...from lack of grease....

I ended up putting in cheap greaseable version off ebay for 140$ or so...works fine on my lift...