Misc. vibrations, seeking input

I've already read a ton on the infamous vibes that plague our 2nd gens, but I'm looking for some advice on what to try first. I've got two conditions going on with my truck...

Truck: 2015 DCSB 4x4 TRD O.R. A/T
Tires: BFG 265/75/16 AT KO2
FR SUS: ToyTec 2.5" 521600 Coil, ToyTec 0.5" Top-Plate Spacer, 5100's
RR SUS: ToyTec/Deaver 2.0" AAL, stock TRD Bilstein HD shocks

*no diff drop*, *no additional rear axle shims*, *no carrier bearing drop*, *stock uca's*

Vibration #1:
First noticed after the tires, but before the lift. Light, quick pulse felt through the steering/seat between 52-60mph, most prominent at 55mph. Since this was around before the lift I'm leaning towards thinking a front tire might be slightly out of balance.

Vibration #2:
Rear end "shudder" felt through seat/steering when taking off from stop, between 10-20mph. I think this is the infamous driveline vibration.

Obviously if the first one is a wheel out of balance, that's an easy fix, but it doesn't bug me quite like the rear end shudder when getting going from every stop sign. This is the one I want to countermeasure ASAP.

My questions are:
--Should I start with rear axle shims? (If so what degree)
--If I install aftermarket rear axle shims, do I pull the factory rear axle angled shims out?
--I noticed during install the factory shims have the narrow end pointed towards rear of truck (rotating front/input of axle down), isn't this counterintuitive to a straight driveline?

Thanks,
Hunter

 

Parts are cheap I would do both the carrier bearing drop kit, and 3 degree shims

 

When the 3degree shims go in, do I pull the factory shims out?

 

Did not realize the factory had shims. But yes you do.

 

OP , not sure why you would have factory shims . Did you get the driveline vibe TSB done ?

 

Bought the truck new three weeks ago.

The factory leaf pack had 3 leafs plus the overload. The shim that was already there was painted black and assembled with the factory leaf pack. It appears to have come this way right off the assembly line. I was there when the truck came off the trailer until I drove it home, so the dealer didn't install it, and I didn't install it, so....

I'll attach a picture in just a minute

 

I just bought mine to and just looked at it. That's not really a shim. A shim is small at one end and progressively gets thicker near the other end. Mine is like a 4 inch flat piece the same width from front to back. Maybe 3/8 of an inch

 

Interesting , I was under the impression that the new springs had s tapered bottom rather than a seperate shim

 

Not good pics but here are some

 

Mounted a GoPro underneath my truck aimed at the Carrier Bearing, can definitely see some wobble in it when accelerating:

http://youtu.be/qFnaapThWhs

 

Since my truck has the OEM shims angling the diff input downward (narrow end pointed rearward), lets assume these at a minimum are 1.5deg, if I simply rotated them around this would change the rear diff angle by 3deg, is this worth a try?

Conversely, if I removed them, and installed 3deg ToyTec shims, this would be a 4.5deg change from where the diff is now...


In the meantime, I ordered the OME CB drop kit, will try that first since its the easiest install. I know there's not a magic bullet for all trucks, but does anyone think the 3/8th's drop will fix it? Is it worth adding washers on top of the 3/8 drop spacers to simulate a 1/2", or 3/4" drop?

 

Mine definitely are angled/tapered:

 

Yeah mine are to after crawling underneath to see it. I would try the carrier bearing drop first. Then take out that shim and put a 3 degree one in. When I did the Toytec 1.5 AAL in my 2010 I put the carrier bearing drop in and the 3 degree axle shims at the same time. Zero vibes at all

 

How do you know what shim angle is already in there ?

 

Don't know, it was a guess, just to show that pulling that one out and inserting a 3deg from ToyTec would actually be rotating my diff more than 3deg (3deg + X deg that the oem shim already has it rotated down).

 

You could probably compare the thickness of both the thick and thin ends of the two shims to see if the 3 degree shim is a greater angle

Have you read the " fix your driveline vibe " threads for tips on calculating how to go about resolving your driveline vibes ?

 

If the shim is thick end to the rear , it rotates the diff up

 

Thicker end is forwards facing

 

Many of them, which one specifically?