Driveline Vibration?

[Sin City Trail Boss]

Hello guys, I could use some feedback from some of the experts on here.

 

So I have a wicked steering wheel vibration, also a very noticeable vibration in my drivers seat. I feel it the most at 40 mph, but its constantly present from 30-80mph.

 

Here's my dilemma. About 2 weeks ago I removed the rear block from my Trail Boss. The block was 2". For those curious, I wanted to level my truck and this was a way cheaper options, plus I like the easier accessibility now to the rear bed.

 

I went to a shop and had them make me new u-bolts since the stock ones would be too long. When I was there, the owner told me that there is a slight chance that I would develop a drive line vibration do to angles changing as a result of removing my block.

 

He did tell me that he didn't think this would happen, but told me that is is a possibility.

 

U-bolts were torqued down to 120 ft/lbs.

 

In my opinion, I think it's the tires. I have taken these in 3 times to get balanced and evaluated. The dealership told me they ran all sorts of tests, to include a picoscope sensor and drove it for 40mph.

 

Dealership told me that they were within "tolerated specs" from both GM and Goodyear. However, an independent shop I took it to said all 4 had excessive road force numbers and took a lot of weight to balance.

 

So at this point, I am not sure if its my tires or the fact that I removed the block, or maybe both.

 

My question is this: How likely is it to develop a drive line vibration due to removing the block? Should I add a shim to the rear to adjust the angles?

 

I would appreciate any feedback. I don't want to spend 1K on new tires if it is indeed the block that made it worse.

 

Thank you!

 

 

 

 

[mafd2]

Not sure about removing the block on the TB but members here have installed drop shackles and developed a slight vibration on decal around 30 mph.  We reversed the factory pinion shim and it corrected the problem.  You have a broader range of vibration though.  Does the TB have a pinion shim or just the block?

[Sin City Trail Boss]

5 minutes ago, mafd2 said:

Not sure about removing the block on the TB but members here have installed drop shackles and developed a slight vibration on decal around 30 mph.  We reversed the factory pinion shim and it corrected the problem.  You have a broader range of vibration though.  Does the TB have a pinion shim or just the block?

Was just a 2" block

[Sin City Trail Boss]

12 minutes ago, mafd2 said:

Not sure about removing the block on the TB but members here have installed drop shackles and developed a slight vibration on decal around 30 mph.  We reversed the factory pinion shim and it corrected the problem.  You have a broader range of vibration though.  Does the TB have a pinion shim or just the block?

Was thinking of adding this 1/2" block since it would perfectly level it since right now it's about 1/2 lower on the back.

 

Do you think this will help if it is an angle issue?

 

Adding this would only be a 1.5" difference from stock.

 

http://www.calvertracing.com/store/lb02-lowering-block12-thick-w-916-pin-p-203.html?zenid=1018cbcf65810c1d68bc22221d3b2c1a

[mafd2]

Check this thread out page 2.  Member 19trailbossRic installed 2" drop shackles using the 1.5" hole.  I don't think he's having any vibration problems.

 

 

Edited September 19, 2019 by mafd2

[Sin City Trail Boss]

18 minutes ago, mafd2 said:

Check this thread out page 2.  Member 19trailbossRic installed 2" drop shackles using the 1.5" hole.  I don't think he's having any vibration problems.

 

 

Good info. Seems like many did need to rotate the shim on theirs. But seems like they were all experiencing vibration at slow down. Mine is at the steering wheel mainly.

[mafd2]

Yea that's what I was saying.  You have a different vib issue.  So you didn't have any vib before removing the block?

[Mikebtte]

You need to check pinion angle vs transmission tailshaft angle. You can cause damage if they are not correct.

The rear axle can me shimmed if needed to add angle.

You will need to go to a driveline shop for propped repair. A dealership prolly won't deal in this issue.

[Sin City Trail Boss]

12 minutes ago, mafd2 said:

Yea that's what I was saying.  You have a different vib issue.  So you didn't have any vib before removing the block?

Yup I did, but now I don't know if this has made it worse. At the same time I did the block, the dealership rotated tires. So now I'm paranoid as to whether it is the tires I'm feeling, or if I messed up the angles with removing block. I always had seat vibration, but the steering vibration has gotten bad.

 

I guess I will rotate tires back and see if it makes a difference. Thank you for your help

[mafd2]

If you had vib before I surmise it's a tire issue.  IDK..

[bh069me1]

Same issue here..2020 trailboss..swapped tires, still have the factory wheels..my truck does not have the pinion shims..just the 2" block..I would like to bring the rear of mine down also.

Did you come to a solution for the vibration.

My dealer is of no help whatsoever 

[blckblt]

Do you have any ability to swap tires/wheels as just a test?

[bh069me1]

I do, but time hasn't allowed me to be able to swap just yet.

Local tire shop says tires and wheels are fine.

Dealer says all is is within tolerance.

Feels like pinion angle (my truck does not have any shims at all only the blocks in the rear) or the cv joints in the front are bad, there is no defined answer on how much is too much play for those though...wondering if I need to adjust the pinion angle with shims at this point

 

[tainoxl]

Was this ever resolved??  I just got Trail-boss Replicas in 20 x9 and am having weird drive line vibrations also.  I have 2020 Lt with2" level.  The problem is always there when I run 20" wheels. We tried three different tire combinations and two sets of wheels, same vibrations.  Put the factory 18" wheels with 265 60 18 s and its smooth.  I have an appt with the dealer but Im thinking I might be wasting my time and money with them as they are just going to tell me to put it all to stock.  

 

 I do have 1.5" factory rear leaf spring blocks from my 14 silverado, wonder if using them would change the angles and fix the issue.