also check your engine mounts. open the hood, block the wheels, apply ebrake, foot on the brakes, drop it in to D and step on the gas abit and watch the engine for movement should be very little.

 

Ok so I think I have finally come to conclusion of why I'm getting this annoying vibration.

I believe it has to do with the pinion angle being slightly off after the shackle install. It shutters when accelerating from a stop, and vibrates at lower and higher speeds where it's most noticeable. I have taken it to two drive train shops to have it all inspected, and been told the angle is fine.

But after plenty of research and trial and error, it seems like plenty of other blazer owners have ran into this same issue after a 2" shackle lift. It's weird that it seems to be a hit or miss type of thing as some have had no issues with even higher lifts. When doing a bit of research before I purchased the shackles, everything I found said it would be fine with no changes needed. Looks like I should have done more research for the downsides some people have experienced.

When I push the car forward while in park, you can see the pinion bind quite a bit. I also took the driveline off and there seemed to be no vibration. U joints were replaced, and I also replaced the tranny mount. So next I'm going to buy some pinion angle shims and try to change the angle to compensate for the change when under torque.

It may not fix my high speed wobble/shake, but I'm sure it will at least fix my shutter from a stop.

I will update after my findings on this.

 

did you check your driveshaft for balance..missing weights?

 

Ya there are no missing weights or anything. I picked up some shims that go from 2 1/2 to 3 1/2 so I'm going to see if that makes a difference.

 

Just a quick update:

Put the 3 1/2 degree shims on last night and took it out. Definitely notice a huge difference but the shake isn't completely gone. As far as the high speed shake, it seems to be close to completely gone. The shutter is now only noticeable when I totally romp on it from a stop, where is was there no matter how light I was on the throttle before.

The mid speed shake is the only one that is still bad enough that makes me want to switch to a larger degree.

I'm going to go pick up a couple 6 degree shims, and hope that will completely rid my problem.

 

i know you said you looked at your drive shaft....but when i lifted mine the shaft moved back out of the trans a bit and i had to have it re-balanced.
i had to mark the position relative to trans end and they re-balanced it. that took care of what the shims didnt fix for me.
also...have you checked the front drive shaft u joint?

 

Hey I was reading your all you said
When my Friend did his blazer up to look like a ZR2 he raised it 2"
we needed to get the drive shafts axles and stuff to make it right because they were now too short
you lifting the ZR2 2'' sounds like the same thing he went threw
I just wanted to give you this lil bit of info
your pitch on everything may be off and off balance or not seated right
I just wanted to pass this lil bit of info to ya

 

I'm happy to say that after installing the 6 degree shims, all vibrations are gone.

Thanks for all of your guys help.


Can't wait to go tell the guy at the drive train shop that argued with me that 6 degrees wouldn't do anything but make my vibrations worse. And wanted to sell me into a $1000 dollar driveline instead. kept insisting my angles were fine.

Thanks for all your guys help

 

congrats on the fix.

of course the shop wanted to sell you 1000.00 of goodies.....
..what could you possibly know right??

makes the job that much more rewarding.