Bad caster will feel like driving a skateboard with a blown out wheel.
Or a shopping cart when the front wheels are going too fast to maintain any sort of stability and they start flopping left to right.
Steering wont naturally be inclined to return to center after turning.
You can usually speed through instability caused by bad caster and it'll smooth out.
Havent ever experienced it... but from what I've been told you'll know when your caster isnt adequate.
I have marlin front springs that sit pretty well flat. '85 frame. Front drop hanger 3". 5.5"(or 6.5" shackles) dont recall at the moment. No shims. Front high pinion is at 5 deg. Low pinion was same pinion angle.... according to 4crawler's info my caster is right on point I guess. Truck drives great.
@liveoak Do you know what angle your t case flange is at? rear should be "down" what the front is "up" and is it factory?
I'd think the angles are off regardless of a CV shaft vs 2 single joints... in any event, did you have vibes one way and now you dont? Or are you strictly based the driveshaft type on theory?
Sounds slightly interogative... but just genuinely curious. I have more time than I care to admit into CSI'ing my driveline angles. Just looking for more info that I can add to my driveline knowledge bank, lol