Rotational hum post lift....need help

so I've searched through here and coming up with different results so figured I'd be straight forward and ask

I installed my lift Wednesday, 5100/885 at 0 5100/AAL in the rear. Mounted Falken Wildpeak 265/75/R16 on SCS SR8s. This is on my 2015 dcsb 4x4 TRD OR. Had about 11,500 miles on it so everything was in great condition and thanks to all the expert knowledge on this forum, I was able to install it myself with no issues.

Got it aligned yesterday, took them a while but they got it done here is snap shot of the specs. Top half is before bottom is after. I should add this is on stock UCAs


So now the issue I am having is, post lift I am noticing a rotational hum that definitely sounds like it is from the front and as I speed up the hum speeds up. It's almost as if I were rubbing something but I looked and I don't think it could be that. I tend to feel it in the foot pedal but nothing in the steering wheel.

I will say, the only issue I had during install was balancing, he had a hell of time balancing them and the front driver side wheel ended up taking 8oz to balance. My first guess would be that this is the issue. The hum is very light and if I turn the radio up I don't even notice it at all but I know just turning the volume up isn't the right answer.

What are your thoughts? I was just looking for some feedback before I start paying to have it looked at or have th wheels re balanced.

Thanks in advance

 

subbed for responses... having the same issue after installing Icon stage 2 lift with Dakars in the rear.

 

Rotational hum after a lift is 99% probably caused by the left front needle bearing in the front differential. Your CV sits at just enough of an angle now to put off axis pressure on the needle bearing = vibration. There is a huge thread about it here on TW. ECGS makes a bushing to replace the needle bearing in the diff. If you buy the bearing removal tool from ECGS it is a super easy job you can do at home.

 

Ya I read that and from what I got out of it was that it was more of a consistent vibe at higher speeds however you notice this most on mine around 35mph and it's not consistent but more as the tires spin. Basically a very slight vibe every second or so.

Now second question, if it is the needle bearing, is this dangerous to be driving on until I can get it done? Do I have to worry about it severely damaging anything else in the meantime?

 

In my experience I could feel the needle bearing issue at all speeds. No, it is not dangerous, in Thierry the bearing could implode eventually but I drove on mine for a long time and when I removed it there was just scarring on the bearings.

 

O ok then. Thanks for your quick responses

 

Were the tires road force balanced? That's a lot of weight on one wheel. The tire tech should have tried rotating the tire on the rim to see if either were out of round.

 

No they weren't road force balanced I know that

 

2 things I would do.

First, demand a new tire. 8 oz on one wheel minus a damaged bent wheel of course is unacceptable. Could be anything from broken belts to separated plies which in turn could cause a hum/vibration.

If number one doesn't resolve it, I would accelerate slowly until the hum is pronounced. Once it is steady, and safe to do so, veer back and forth. Not like scrubbing tires on a NASCAR restart, just enough to shift load from one side to the other. If it worsens one way and gets better another way you likely have a hub bearing failing.

The lift changing geometries of the front end components could be just enough to alter the load and make it audible now vs waiting for it to worsen on the old set up

Either way, I would replace that tire or swap it with another wheel that balanced ok and rule out the wheel.

I used to cringe putting anything over 3.5 oz per wheel, I woud never do 8oz or accept that.

 

The best way to determine if it is front diff bearing issue (assuming you are 4wd) is to put it in 4wd. If the vibration goes away, that's your issue. If not 4wd, you don't have a front diff, and it's something else.

 

subbed

 

Thx for the replies. I'm going to get them re balanced for starters try and get a road force balance and if not get the tire replaced.

Will try the 4wd to rule out the diff

 

This is the big ass thread that covers the differential needle bearing vibration. https://www.tacomaworld.com/posts/11966217/ @Evenflow
East Coast Gear Supply manufactures the bushing that fixes it.

 

I had mine road force balanced at a local Toyota dealer for $40. Not sure if it was during a free service though.

 

I recently replace my needle bearing after my 3in bilstein 5100 lift. Once on the lift I grabbed my driver side cv axle and gave it a wiggle, there was so much play with the factory needle bearing. After the ECGS bushing install there was very little to no play with the shaft, also no more hum. Check the 4wd procedure others mentioned to clarify that the needle bearing is the issue and go from there...
Personally with any size lift or high mile truck I would recommend just replacing the crap OEM needle bearing to the ECGS bushing.

good luck

 

Sounds like a needle bearing as others have stated. Mine started almost right after my lift and was most notable at 35 MPH. Strange though - it seemed to have stopped about 150 miles ago - or I'm just desensitized to it

Looks like your caster numbers are a bit low too. Does the truck wander at all? I have similar lift specs - except 885 coils - and I was able to get 2.4 ( or something close - can't exactly remember) and it drives great.

That big ass needle bearing thread linked earlier is a good read. Confirmed for me the problem and solution.

 

Ya I confirmed it today that the needle bearing was the problem. Drove around 35-40mph was noticing it and switch it into 4H and it instantly stopped.

Also, no my truck doesn't wander at all. Has pretty good road manners with the lift and alignment

 

*Update*

So today I went and got my wheels re-balanced since, as discussed earlier, it wasn't the best job. Found a shop locally that could do the road force balance and decided to give that a try. Let me tell you...very happy with the results. Even the steering feels a lot tighter. But most importantly, I drove it about 50 miles afterwards and NO VIBRATIONS!

Here is my theory: I think that my front driver side tire was so unbalanced that it was causing the CV axle to rub in the front diff. While the tire was off, I grabbed the CV to see if there was a lot of play in the diff but there really wasn't a lot at all. The tire that was on that side was the one that took 8oz initially to balance but took half that the second time around.

Now I already ordered the bushing from ECGS, so if I still have the vibe and maybe I just didn't notice, or if it returns then at least I will have it to install.