LSchicago

I have a 2013 RCSB with 2/4 (axle flip) McGaughys drop, and have a slight vibration between 10-25 MPH. Will the 2.5 degree shim fix this? Thick part to front?

rojizostang

The shims didn't help mine either in front or back.

When you raise the rear end (or lower the rear of the truck, however you want to say it), the pumpkin starts tilting upward. To me, if you place the shims in the front, it makes it worse. I believe the shims should be in the back to help tip the pumpkin downward as was originally, imho. I'm not running any shims now and it's about a 6 inch drop in the back, more or less.

What did help was removing the spacer from under the carrier bearing on the drive shaft. Eventually I cut the remainder of the mount off under the carrier bearing and mounted it directly to the cross member. The vibe is barely noticeable at all, if it even exists.

UNBROKEN

iTrader: (1)

Every truck is different. Long story short you're looking for the difference between the driveshaft and pinion flange to be -3° with the pinion facing down. With a flip kit the fat end of the shim will always be to the rear.
The easiest way to find the angles these days is a degree app on your phone...we used to have actual measuring tools to figure it out. lol

superchargedv8

Mine does the exact same thing after the 2/4 drop but mine is a 17 rcsb.

LSchicago

The shop finally got me back in today. Installed the 2.5 degree shims fat end toward the rear, and removed the center bearing support spacer and the vibration is about 90% gone. I'll live with it for now. Also installed 1" tall Energy Suspension bump stops, and now have a nice smooth ride.

UNBROKEN

iTrader: (1)

Did they actually measure the angles or just slap in the shim you had?
5 minutes worth of research and they could have put in the correct shim and eliminated it completely.

rojizostang

the next step is to trim the support that was under the bearing spacer all the way down to the cross member. It would probably get the last 10 percent.

I did that on mine but you will have to re-drill the holes for the bearing bracket. When you lift the bearing bracket all the way to the cross member, it deflects the location of where the bearing support used to attach, compared to the holes that lined up with the spacer installed and the rest of the bracket. Those are the things that worked for me to eliminate the vibe.

LSchicago

No they did not measure. I bought the shims, and brought to them. I really did not have time to measure and chase shims and neither did they. The shop is down one guy, and I waited a week just to get this done. Also, I'm probably going to raise the rear 1 inch, to give the rear 1/2" or so of rake. It's about 3/8" low in the rear. I will probably take it to a driveline shop when I get back from our weekend road trip, and decide on 1/2" or 1" rear lift shackles so they can get it exact. My main concern was getting the correct axle plates mounted before leaving.

UNBROKEN

iTrader: (1)

I'd bet when you raise it up it cures your problem. Good luck with it.

LSchicago

That would be nice!