60 MPH droning noise after lift...only when throttle is open

Hi,

I have been doing a big overhaul on my 2006 reg cab 4x4. I'll explain all the things I've done, but the short of it is that immediately after installing my lift, my truck developed a speed-specific droning noise. It's right around 60 MPH-- and happens only when the throttle is open. If I let off the throttle it stops. It does not vary by engine RPM/gear. There is no vibration associated with the noise.

Here is what I have done to the truck in the last few weeks:

Front end: 5100s with Wheeler/Eibach springs set at 0. About 2+" of front lift on my reg cab
Rear : New toyota recall leafpacks with wheeler 2" AAL and 5100s
The droning noise occurred after I did the install.

Other work that was due and I did shorty afterwards (no effect on the noise):
New front wheel bearings (left was shot).
ECGS front diff bushing (needed-- removed some noise/vibes that became evident after lift)
Diff oil front and rear is new and up to snuff.

Alignment-- was able to get back within 'specs' although caster is a little lower than I'd like. Truck is driving great.


So now I'm left wondering what will relieve this noise. I have AT tires that are fairly cupped and noisy-- so perhaps this is contributing?

What else could be causing a speed specific-throttle open noise? CV angles? U joints? Tired diff?


I searched but couldn't find anything definitive. Any input appreciated.

 

Wouldnt be the tires if it is only happening with throttle open. I had the same issue and it ended up being a ring and pinion problem and I ended up having to replace or rebuild the third member Here is my thread:

https://www.tacomaworld.com/threads/new-tacoma-owner-drivetrain-whine-question.447546/

 

Also you might want to check your rear driveshaft angle and determine if you need a carrier bearing drop, and while your under there, fill all your u joints with some fresh grease to see if the noise changes at all. Also maybe look into axle shims if you lifted the rear significantly.

 

Excorcist, thanks for the reply and information.

It makes sense that it's not the tires-- since it is throttle dependent. The sound is not like a gear-whine that I am familiar with. It sounds much more like the low drone sound that is made when someone is blowing air over the mouth of a jug. Kind of sounds like it is coming from directly under the driver's seat or the drivers side front wheel; obviously sound can move in weird ways.

What makes the most sense is that it is related to an angle that changed after the lift. The regular cab does not have a carrier bearing. I lifted the rear 2". I am wondering if my U-joints are the culprit. I put some grease in them recently, but one the corners of one didn't shoot out grease like the others.

 

Gotcha, being that you are in "rwd" when you hit the throttle it makes more sense to me that the noise would be coming from rear end more than the front just because there is no torque being applied / relieved when your are on / off the throttle to the front end. If it is more of a hum I think that sounds like more of a bearing than anything. Sorry I couldnt be more help

 

Also you can try putting it in 4wd on a long straight smooth dirt road to see if the noise is present or not to try and narrow it down.

 

An update...

Today I was driving with a big load of stuff in the back and my hitch mount bike rack and a few bikes. Easily 500 lbs. Guess what-- no noise. Quiet as a mouse-- besides my loud tires. This makes me think that the noise is a driveshaft issue that appeared after the lift. The extra weight brought me back down to stock height.

I checked it out a few days ago and the u-joints appear to be healthy and have no play in them. The slip shaft has some play-- not sure if it's beyond normal.

It sounds like this is a known issue for the 1-piece driveshaft on the regular cab (found one or two other posts about this). Some report that flipping the driveshaft will resolve (or hide) the issue. I think that is my next step-- also maybe try driving around in 4WD with the driveshaft removed to verify that it is the culprit.

Any other regular cab guys had this issue after lifting?

Edit: here is the post where I heard about the issue:
https://www.tacomaworld.com/threads/how-to-reg-cab-rear-driveshaft-flip.191798/

 

How many miles on your truck? I think that your driveshaft shouldn't have any play in the slip joint. I you can push on it and feel some, that's one problem. Also, you can have bad u-joints, and not be able to diagnose that when the shaft is still on the truck. If you pull the shaft, and start rotating the u-joints throughout their range of motion by hand, anything other than smooth motion is bad. At least driveshafts are easy to pull.

 

130K on the truck. I am going to pull the driveshaft tomorrow and do a better inspection. If the slip joint is shot-- I'm probably looking at a new driveshaft right?

 

Most likely the driveline working angles are outside of acceptable limits - which will cause torsional vibration that is worse under load like you're experiencing.

Do some reading on measuring and calculating driveline angles, and adjust your pinion angle with tapered axle shims. With a one-piece driveshaft, that's about the only thing you can change.

 

Sure sounds like drive shaft.
Shaft 101 http://www.4xshaft.com/driveline101.asp
Harmonics http://www.customdriveshafts.com/vibrations.asp
Geometry 101 http://www.customdriveshafts.com/driveline101.asp
Slope vs Angle http://www.customdriveshafts.com/tech_slopesVSangles.asp

 

probably just need to adjust pinion angles to cancel vibes out.

 

Carrier bearing

 

I think a driveshaft shop may be able to put a new spline in. For a single piece shaft, your input (transfer case) and output (rear diff) flanges should be parallel. That should make the vibes from the front u joint equal and opposite of the vibes from the rear u-joint, so they cancel each other out. In theory the flanges are parallel from the factory. Also in theory a lift should not make them come out of parallel, but it's worth checking. You'll need an angle finder to be sure. You can get a Wixey on Amazon, or harbor freight sells them.

 

Well,

I pulled the driveshaft and drove around. Quiet.

One of the U-Joints (closest to the pinion) seemed a little tight, so I replaced it. I also greased the slip shaft; it didn't look very worn- the shaft had this blue coating on it. It was pretty dry, so I greased the heck out of it.

Put the driveshaft back in. Drove around. The sound is back. No change. Flipped the driveshaft 180* and drove around. Same thing.

I measured my angles and it looks like the T-Case output and the Pinion are within 1* of each other. For a 1 piece driveshaft; that seems pretty good I think.


What are my next steps here? Experiment with shims? Tom Woods 1 piece with a double-cardan ? Could it be a bearing at the T-Case output or Pinion that is worn and starts making noise when the driveshaft hits a certain speed?

 

1 degree is the difference between good and aweful - you're going to need a digital angle finder accurate to .1 degree to get it right. There are free apps for iPhones that will do this, not sure about other phones. Or you can buy a standalone digital angle finder.

 

Update:

I installed some 3* shims and the noise has greatly reduced.

Before installing, I measured the t-case output and the pinion and they were very close to parallel (as they should be). I measured with an angle finder on my phone and also by measuring the distance between the tops and bottoms of the flanges.

My theory about this (which could be totally wrong) is that the rear AAL lift increases the driveshaft angle, and while the flanges remained close to parallel, the driveshaft angle exceeds the happy operating range of the U-Joint near the T-case. Tipping the pinion up alleviates this to some extent.

It seems like this is especially problematic for reg. cabs, since they have a 1 piece driveshaft. On a long bed, the shaft angle seems close to the max that a u-joint driveshaft will tolerate. My '96 had a double cardan joint and it didn't seem to have the same issues.

Hopefully I am vibe free when the bed of the truck is loaded down also.

 

I have the same issue on my '06. Stock with the recall rear springs. I was planning on leveling the truck with 5100s soon. Looks like I need to get some shims for the rear. Can you post some pics of the shims installed?

 

Caltech,

Sorry for the delay in reply. I'm on a road trip in Southwest Utah-- great mountain biking and 4WD trails.

Bummer that your truck is doing this after getting the recall springs. Is it a regular cab?

My truck is covered in red dust, so here is a picture I pulled off of TW. Not my truck but same idea. The skinny end of the shim is pointed towards the front of the truck. I got a 3 degree shim-- it's the type that comes with a new leaf spring centering bolt-- so you bolt it right into the leaf pack. This seems more better than the kind that just slips under. I have no idea if 3* is the correct shim angle; you might also try 2*. I have heard a rule of thumb of 1* per inch of lift-- I assume your truck is taller with the recall leaf pack. If you have the regular cab, there is definitely something special (not a good special) about the one piece drive shaft and how it responds to changes in driveline angles. Good luck and post an update if you solve if on your truck.

 

You said you drove around without the drive shaft....I'm assuming you just took it out, threw it in 4HI and drove around? I was considering doing this to diagnose a similar issue I'm having. When doing this, anything special to consider to make sure you don't screw anything up?