So my 3" lift is probably more like 4 1/2 inches> I put in a SYE and CV rear drive shaft. It took 8 degrees worth of axle shims in the rear to get the CV shaft pointing to the correct angles. The rear driveline vibes seem to be gone, but the front is still vibrating pretty bad. How do you fix that? The steering geometry has to be right, so it's not like I can change the driveline angle. A little help please...

 

U joints might be bad or the swivel ball joint not sure what the correct name is. Pretty simple to rebuild. Just did mine last week. There's also plenty of videos and how-to's out there.

 

Front DS needs to be rebuilt or replaced.

 

Pinion angle takes priority over steering geometry (caster).

 

Technically... You could rotate the knuckles.

 

Adj. upper CA's will adj the pinion angle for you, I have both Adj. U/LCA's on my 4 1/2" lift, shims were required in the rear also.

 

I took out my front drive shaft and the thing drives perfect, with no vibes. My front pinion is pretty level, like it was not a lifted vehicle. I have aftermarket longer lower control arms but stock uppers. If I put on longer adjustable upper control arms to bring the pinion angle up, it will screw up the steering geometry right??? So what is the happy medium? Or do I just make the front pinion in line with the front driveshaft and let the steering wander all over the place? What have you guys done.

 

With the front drive shaft out check the u joints. Also rotate the CV joint by hand, see if it's catching or binding at all. Mine had very little bind but was causing lots of driveline vibes. If your u joints are bad prior to your lift, once you install the lift it will immediately expose any bad joints.

 

The slip yoke on front driveshafts usually goes bad and causes a constant vibration. Check that.

 

The front drive shaft doesn't have a slip yoke.

 

You found the problem then.

You need aftermarket uppers to kind of meet in the middle. Adjustable would be ideal so that you can play with it and get it dialed into the optimum setting but you could buy a pair of uppers specifically for 4.5 inches (assuming your lowers are specifically for 4.5 inches as well).

At this point though you're getting into the range of lift where you really should either get drop brackets or long arms though because your LCA angle has got to be getting pretty steep by now.

 

Yes the driveshaft has a slip yoke within itself. http://www.4wheelparts.com/Drivetrai...FRJZhgodj18A1Q

 

You linked to an actual slip yoke. You are referring to a (splined) slip joint.

As I said, there is no slip yoke on the front drive shaft.

 

That is the slip joint aka slip yoke for a front shaft.

Here's another for you. All splined "slip yokes". I know what I'm talking about man.
http://www.dennysdriveshaft.com/c451...riveshaft.html

 

That knuckle close to the xfer case, cardone joint I believe its called, was causing it on mine. I rebuilt the whole drive shaft and no vibes now.