Driveline grinding/vibration after lift

Hi all. I've got a 2021 4Runner and just had a 3 inch lift installed. King shocks with Total Chaos UCAs and LCAs. I'm now experiencing a noise that's similar to the noise people experience when the needle bearing is failing, but my symptoms ONLY occur while in 4 Hi.
I didn't initially have a diff drop installed, and put about 100 miles on the vehicle before my parts arrived and I was able to get it installed, but I still am experiencing the noise.
Essentially, when in 4 Hi, I hear a grinding/howling noise. It *sounds* like it's coming from the front right, but I can't be sure. At its worst, I can feel a slight vibration through the steering wheel. The noise/feeling occurs with the initial throttle input, and again when you let off the gas. The noise only remains constant if I give slight throttle input until the grinding/howling noise starts, and then maintain a light maintenance throttle to keep a steady RPM. It's not dependent on RPM, but once started, it does go away when the RPM changes. It seems to be making the noise when a light torque is initially applied or removed from the driveline. For example, it won't make the noise with heavy throttle application. It's louder at higher speeds, and isn't really noticeable under 50 MPH.
I've lubed the drive shafts, and haven't noticed any excessive play in the front drive shaft or front axles. I drained the diff and transmission to check for metal, but the fluids were clean. There is a slight amount of rotational play in the front diff when the vehicle is in 2 wheel drive and I manually rotate the front drive shaft by hand, but I'm assuming that's normal.
Any driveline experts in here that may be able to give me a direction to look?

 

got a video of it?

 

I tried today, but the only recording equipment I've got is my phone, and the ambient noise overwhelmed the driveline noise. Once our roads refreeze or dry out (I'm in Alaska, and the roads are super wet and dirty right now), I'm going to borrow a gopro or something similar and mount it underneath to try to capture the noise.
I do have a short clip of the play in the front drive shaft and the noise from the front diff when manually rotating the shaft back and forth. Posting it in the event I'm incorrect and it's not normal.

https://youtu.be/VU-IAoyEc6k?si=Ra8RkLI-m8QMO1CL

 

All of the vehicles I've owned/driven have that 'clunking' sound…except my 21 Pro. I just checked it and the front driveline barely makes a tic sound…I think you’re looking at a new front diff at this point.

 

Hell yea! My wife lived in Tok for quite some time. She often tells me I wouldn’t survive up there. Hahaha. I’ll check out what u linked

 

That's unfortunate if it turns out to be the case. As mentioned earlier, I had the fluids drained and filled post lift after putting a couple hundred miles on it with no diff drop, and the drained oil had no evidence of metal shaving or pieces. I'll definitely look into it harder now.
And I wouldn't survive in Tok, that place sucks, even when you're not freezing your balls off. Lol

 

I’d check & see if that u joint needs some grease on the zerks. ujoints need it every 15k typically

 

That was one of my earlier thoughts but if you look really close there it appears that the Cross and Yokes move in harmony, if there were any wear issues with the needles you'd likely see the end caps move and/or the Cross wobble with respect to the Yokes. But yeah, the overall joint looks a bit 'dry'.

 

First thing I did was hit all the zerks until I saw new grease squeezing out. Unfortunately for me, I never double checked behind the dealer when we had it in for its service, and I may be the first to have greased the drive shaft since we got it from the showroom floor. Part of me is hoping it's as simple as the u-joints being worn since they got their first grease after 60k miles.

 

Well I don't wish to sound negative so hopefully it's something else much simpler than what I only know about. Question, did you bring in your truck for scheduled service? I found copy of a printout that my dealership provided when I went in for a full fluid change (transmission, engine, xfer case and the rear diff.) at 40K. I had to verbally ask them to be sure to grease everything (and I checked afterwards.)



And this was something I found (can't remember if it was on this forum) regarding some 'recommended' service items.


You can see just how often the driveshafts need to be tended to.

 

I may have missed this in the thread, but is the sound impacted by turning at all?

good luck!

 

Yeah, they were supposed to have greased them. I didn't check, because it's so easy to do that I didn't think it'd get skipped. Maybe they did, but the zerk surface matched then drive shaft surface perfectly, and I could not find any indication that grease had ever been moved through the joints. On me for not double checking.

 

Nope, straight line, and primarily audible at highway speeds. I can hear a slight thrumming noise below 45ish MPH, but if I wasn't listening for it, I'd probably miss it.

 

I knew I had this somewhere...*I think* it may be something applicable to your case and something worth pursuing.

T-SB-0075-23 Cyclic Growl/Groan Noise from Front Differential

 

That's the TSB for the needle bearing. The symptoms for that include the noise going away when the vehicle is put into 4x4.
Mine doesn't happen *until* it's put into 4x4.
I appreciate it though!

 

Not the first time part of my post vanished into the ether.

To be succinct about my posting of the T-SB...It's the part that refers to the "Differential, Dynamic Damper" that I'm referencing. Note the 'built before' date reference.

Will this solve your situation? I dunno but may be something to try since the Toyota Engineers have this part to address what sounds like a similar condition/noise.

Looking at the parts diagram, it may be worth a close inspection of all the mounting hardware and to check all fastener torques...maybe its something as simple as a loose bolt, somewhere around the diff.

 

I would focus on what got touched and/or replaced. Might have to reverse the lift.

 

Personally checking the mechanical connections is on the table for this weekend. I had it into the shop for a full re-torque on all components installed, but didn't make any difference. I'm really hoping I don't need to reverse the lift as the OEM stuff was worn out and is now in the trash.
Plus, 3 inch lift is pretty standard on the T4R. Still holding out hope that it's worn u-joints on the front drive shaft, but the only reputable driveline specialist in town is booked 6+ weeks out. I'll be making an appointment with them if I don't find something this weekend.