I have 1991 chevy k1500 pick up and i replaced the front U-joint at the front diff and put a 4WD actuator eliminator in and got a severe vibration at about 60km/ph in 2High, would it be possible my front and read drive shafts are out of phase? Also replaced my transfer case with one from a wrecker about 6 months ago (it had 90 days warranty) but never had 4WD i just figured it was the actuator, if i put it in 4High with the original actuator still had vibration, with the eliminator it does it even in 2High. Where would the vibration more likely be coming from the transfer case, the drive shaft, the front diff or possibly c-v joints or hub? Also noticed a leak at my passenger side c-v joint, I read somewhere else that In 2High with the thermal actuator in the front passenger side spins free, is there anyway to test it?

 

Driveshafts are phased to themselves, not each other.

Pull that front shaft again because this is where your vibration is coming from. Did you get that joint too tight? Is the slip joint wobbled out? Did you install it 180° to it's original position at the yoke?

If it is now vibrating in 2 wheel drive, it means that the differential is still engaged and ground travel is spinning your out of balance shaft.

Allan

 

I also had this problem it ended up being that the u joint was literally barely even noticeable but when measured it was off to one side. This made severe vibration until it was handled