vibration from 25 to 45 MPH

Good job man!! How do you like them?

 

Sonjay- Man, they have met all my expectations! I can't wait to run them off road! Very beefy setup! Nice on road ride, better than the AAL. It changed my rear driveline angles and rear ride height, for the better, and I have even less vibes. I did measure the angles again and although I'm closer, I'm still a few degrees off so I want to see what I can do about that today.

Budis- Here's a pic for a Double Cardan Setup Only, it doesn't matter what Angle A is and it doesn't matter if you measure on a level surface or not, it will cancel itself out, but for your setup, Angle B and C must match perfectly, or as close as you can get them. The vertical rear pinion flange angle must match the horizontal driveshaft angle creating a 0 degree pinion angle. Stated another way, the driveshaft and flange must make a 90 degree angle. If this is already matched up, then your vibration(s) is most likely from another source.

(For a Single Cardan 1 piece driveshaft this won't apply, angle A and angle C would have to match in that case. I have more pics in an upcoming thread)

 

I have a very similar vibration that I can feel in the gas pedal and also hearing with the radio off and the windows up. I just lifted my 2005 4x4 Access Cab with a Toytec 3" Light Coil in the front and an AAL in the rear. I also did the 1" Front Diff Drop as well. The truck drove like a gem before the lift, now with the vibe is just pisses me off. What should be the first thing that I do? Should I shim the Rear Axle or pull off the Front Diff Drop? Thanks guys!!

 

What speeds are your vibrations occurring?

 

From around 20-50 mph. It sounds like I created this thread since I have the SAME problems.

 

I would pull the Front Diff Drop, torque the bolts, and test to see if anything changes, especially if you hear that droning noise at 20mph and it is unreasonably loud. Your rear driveline is also going to need a carrier bearing spacer and/or axle shim to get all 3 u-joint angles on your 2 piece propeller to cancel out to 0 degrees, give or take. That's not easy to do by trial and error.

 

How much of a pain is it to do the carrier bearing spacer?

 

That spacer isn't hard at all, but, you have to reinstall it to make sure that both parts of the 2 piece drive shaft are perfectly straight. That's where most people mess up. The CB can shift side to side pretty far and that can put a kink in the driveline, like this Bottom View of the truck:

 

I personally can pull the Diff drop in less than 30 minutes. You'd be surprised how multiple sources of front and rear driveline and suspension alignment changes can impact a 20-50mph vibration. That's a wide range to have vibes and usually the result of more than 1 source.

 

I am also experiencing a vibration that can be felt best through the steering wheel at 35-45 mph. I have a pretty good feeling its coming from the driveline. I have thought of putting the carrier bearing drop kit in. I am not very fond of using the axle shims and would like to use just the carrier bearing drop if the axle shims are not neccisary. My current setup is an add a leaf setup, and will sooner then later be replacing the rear springs with 1.5 (same as current setup) to 2.5 over stock lift leaf packs. Any advice on this would be much appreciated.

 

The axle shims are not that hard, I can do them in 1 hour because I've done them so many times. You don't have the Diff Drop do you?

 

So should I order the carrier bearing drop kit AND the Rear Axle Shims? Also where can I get the Carrier Bearing Drop Kit? Last thing, will I have to order new rear U-bolts if I install the rear shims? Thanks again!

 

Nope, I'm running a PreRunner (2x4) with the 4x4 suspension. I just have weird feelings about putting anything between the leafs and the axle... There isn't ANY potentially negative effects by doing this?

 

Running 2 u-joints beyond operating angle tolerance can cause premature wear on them and lead to failure. Correcting u-joint operating angles with axle shims is a common practice when changing suspension and driveline components. I currently have custom shims being fab'd up and ran shims from Toytec for a couple of years without issues.

 

The CB spacer is available from OME and ToyTec. Axle shims are available from ToyTec also. I installed rear shims and the ToyTec u-bolts from my AAL kit were plenty long enough. A shim is usually 1/4 inch thick or so, but the leaf pin has to be long enough to stick through the shim and penetrate the axle. It worked fine for me with an AAL kit and new Dakar leafs.

 

So just using the carrier drop would probably not be the way to go? Do you think it would be necessary to use both, or would you recommend just the shims?

Sorry for all the questions, but i am new to the lifted truck deal and just trying to determine which route is best.

 

No problem. I never acutally measured the angles with an angle finder. When I had the 2 piece, I used the CB spacer and 2.5 degree shims if I recall, and had ok results, but not ok enough to stop me from buying a $300 custom driveshaft. I just did trial and error stuff. I now know exactly what my angles on my 1 piece are, and I know how to correct them. It is a lot easier. My truck is also smooth as glass from 0-45 and 50-65. My only vibe now is passing through 50mph and my custom shim should fix that. 4 weeks ago, my truck was miserable to drive at any speed.

 

Great to know. I appreciate the information!! Looks like I'll probably be buying a pair of axle shims along with the carrier drop. I'm sure the 30 bucks is a hell of a lot less than buying a couple bearings.

 

You guys should go to Harbor Freight or Home Depot and get an angle finder and measure. I have a cheap $4 magnetic base angle finder from Harbor Freight that really works surprisingly well. That way you'll know the angles and you can fill in this chart. Then you can check the math of the angles and see if driveshaft theory really works on this setup. 1 or 2 degrees can make a huge difference. I moved on to a better driveshaft because after what I spent so far on my truck, another $300 was nothing.

 

Here's me measuring, from right to left, my rear u-joint, my 1 piece driveshaft, and my front u-joint. I use a piece of flat steel clamped to the flanges to make it easier to measure. Your 2 piece would use a similar approach.