06 4.0L V6 4x4 TRD shudder

Hey Guys,
I recently replaced my 5100's front and back and moved the fronts to click 3 where they were at click 2 before replacement. It lifted about 0.75 inchs compared to before. I reused the stock coils before and after.

I have an icon AAL kits on hand and have not installed it yet. I was planning to but then......

I recently developed a shudder/ vibration in the rear between 15-30 mph however only under slow acceleration. If I let off the gas when it happens it goes away, if I accelerate harder when it occurs it quickly goes away. If I accelerate quicker through the 15-30 mph range it does not occur but driving this way is unique and terrible in school zones/neighborhoods.

stock wheels 265/75/16 KO2's that were recently balanced and rotated. I do it every 5000 miles so I dont think the vibration is tire related.

225K milage. 4x4 TRD Offroad

Do I need a carrier bearing drop?
Do I need new U joints?
Do I need axle slant plates?

Full Transmission flush by Dealer??

Any advice is appreciated.

 

Based on your description of symptoms, it's very likely a driveshaft vibration related to increased pinion angles.

Not sure how high your lift was before -- if you already had 2.25 or more inches, and you added 0.75" of additional lift, that could easily have pushed your driveshaft pinion angle past a critical threshold.

It's not a simple subject, suggest you watch these in-depth and see if it may apply to your situation:


https://www.youtube.com/watch?v=9yJCSQLTVjM
https://www.youtube.com/watch?v=SH2VIoWOQ0E

 

Also, if you have the $$$ you might consider buying the "NVH App", for iOS or Android, to help track down the source. NVH App uses the phone's built-in accelerometers to characterize all kinds of major vehicle vibrations, from wheels to engine to driveline/shaft.

https://vibratesoftware.com/

But most likely, given the added lift, it's the driveshaft.

 

Put it in 4 and drive it, if you don’t feel the shudder then its going to be that transmission fluid service might be required(DO NOT DO A FLUSH) and possible torque converter it’s tired.

 

I believe the third click on 5100 is a 2.75 total lift over click 1.

I know 3 inch of lift is the threshold for issues.

 

Maybe try dropping some clicks & lowering, see if it goes away.

 

Sounds like driveshaft to me (without seeing it and using the given info). This is common.

I'd install that AAL before you go figuring out the angles. That way you only have to do it once. Are you nose high right now?