I recently put on a coast front driveshaft and it feels like I have a slight vibration that can only be felt in the gas pedal. 4.5" lift 35" tires. 08 with auto transmission. Front pinion is up 2.5 degrees from level. Driveshaft is coming down at about an 8.5 degrees. Drivability seems ok with the caster being at about 3.5.
Anyone have any ideas or am I just worried for nothing??

 

Bump : anybody?

 

That's a lot of lift. Over 5* on the u-joint, vibes are inevitable.
You might haw to drop caster some more. Up pinion 1* and see what happens.

 

On advice from a shop that has installed 100's of these I went the opposite direction and lowered the pinion to 1.5 degrees. Shaft is at 7.5 degrees. With a 5 degree difference at the joint, I am getting no noticeable vibes now.

 

Unless I'm missing something. You were a 8.5 "lowered" the pinion and now at 7.5
This doesn't make sense ?

Lowering ups the caster and puts more angle on the DS.

 

That's what I said when I took that second angle measurement. I must have not got a good measurement the first time.

 

Where did you take you measurement? I went setting my axle housing at 0* degrees from here, which should give me a caster of 6*. I need to take and get aligned to verify. Whoops! Forgot to add pic. will update when I get home.

I, am also starting to think that it is the nature of the beast. Going from smooth running CV joints to DC joints, you will feel the slight difference in the smoothness of operation.

 

Took from one of the two round flats on the frond of the diff next to the cover.

 

Yep that's where I measure.

0* is pushing it even with a stock shaft. Lifted forget it.

 

Mine is tilted up 1.5 now which puts the caster at 4.5. Seems to be all good now.