There actually a few phone applications you can use to verify the right angles.
Getting it right is key and you actually want a .5 degree difference not exactly 0.0 etc.
the app i use is from Tremec I just fire it up. put phone on bottom of engine, drive shaft and rear diff, three button pushes and it calculates its all and tells me which ones are out if needed.
Like seeing 3 greens when I check it.
FYI some of the internet videos get it completely wrong on how to calculate it. some think as long as its just within three degrees of each other its ok even if its 20 degree angles. steering wheel shaft is one thing but a drive shaft at thousands of RPMs is another.
And the wrap comment is dead on. MY task force went thru 3 universal joints until I determined how much wrap was going on and fixed the springs up.
