4x2 Lift Vibration

2011 Taco PreRunner QuadCab <<<TWO WHEEL DRIVE>>>

I recently installed Rough Country's N3 2" lift struts/springs up front and N3 shocks on the rear. It's been aligned and rides great, but the rear sat 3/4" lower, so I installed 2" lift blocks.

I now have a low-speed vibration with the related howl. The u-joints are fine, so I contacted Rough Country and they recommended a 1.5" block kit..

When asked how the 1/2" difference and angled block would correct this issue, he couldn't give me a straight forward response. (Their 1.5" block is angled, their 2" block is not.)

When asked which block was recommended for Tacos, because they sell both, he struggled with a response. It was like asking a 3 year old to hand me a 3/4" ratchet.. (face palm)

There are a ton of threads for 4x4's, but I didn't see any for 4x2's. Can someone send me a thread link or enlighten me on which route to go and why it will correct the issue? TIA.

 

If the blocks are angled then they are tapered so one side is smaller to correct the pinion angle after the lift. 3* axle shims might be another option you could use with your 2” blocks

 

Very likely worn u joints or support bearing responding to the lift.

The joints are old and under more stress with the lift, so even though there's no obvious play, they can cause the vibration.

Taper may fix it, but I've seen lots of tacomas do fine with 3" rear lifts no taper.

 

Yes sir, I'm aware of reasoning behind pinion angle correction and thank you for the suggestion.

I can install shims and replace the u-joints, but I'm trying to pinpoint the actual problem, because the block is the only thing that changed. I guess my question is.. Is it the flat block or the u-joints? I'm looking for a rationale before I start the process of elimination.

 

Seems like a reasonable assumption. Just want to be sure it has nothing to do with the pinion angle before replacing u-joints.

 

It's likely a combination of both. Its the flat block causing excessive angles on the u-joints which then causes vibrations. I'd try the shims first, might be able to get away without replacing the u-joints if you just clean up the driveshaft angles

 

I have a PreRunner with an incredibly over sprung 4.5” (supposed to just be 2.5”) lift. Now I’m not on blocks, I have full replacement leaf springs so there is a slight difference there.

I never had driveline vibration issues, I used this carrier bearing drop shim from Ironman4x4, I believe it is 1/2”.

I did replace the carrier bearing and my u-joints as well.