The CRD drive line noise thread

racertracer · **Posted:** Tue Feb 04, 2020 3:46 am

How can i check/test to see if the front differential is the problem without taking everything apart?

WWDiesel · **Posted:** Tue Feb 04, 2020 3:31 pm

racertracer wrote:

How can i check/test to see if the front differential is the problem without taking everything apart?

If it is an 05 model, you can either jack up the rear end and place it on jack stands with rear tires OFF the ground or simply place the vehicle on a shop lift and lift it up until all tires are off the ground, then crank it up, place transmission in drive and bring speed up to level where you were hearing the noise.
If you don't hear any noise while performing this test, it will eliminate everything on the REAR running gear thus eliminating all those parts.
Short of taking the front differential apart for inspection, your options are limited.
They do make electronic listening devices for finding noises where you put pickups at strategic locations under the vehicle and then go drive the vehicle and listen for the culprit noise. (See information below)

Cautions and Notes: wrote:

If you go the jack up the rear end route, be sure and chock both front wheels, forward and rearward real good on both sides before performing the test.
When you perform this test, it will set an ABS light on the dash, but it will go away once you drive it down the road a little with all four wheels rotating.
When you let off the throttle, be sure and slowly & gently brake the rear wheels to a slow stop before placing the transmission back in Park.
Do not think you can perform this kind of test on an 06 model since it has the traction control ABS system.

Wireless ChassisEAR Diagnostic Device Kit: https://www.steelmantools.com/wireless- ... 60635.html
SKU 60635, can be ordered direct or bought on Amazon.
The STEELMAN 60635 Wireless ChassisEAR is a unique automotive diagnostic device designed to pinpoint squeaks, rattles, vibrations, and other noises across a vehicle's engine, axles, and chassis.

racertracer · **Posted:** Wed Feb 12, 2020 3:36 am

WWDiesel wrote:

racertracer wrote:

How can i check/test to see if the front differential is the problem without taking everything apart?

If it is an 05 model, you can either jack up the rear end and place it on jack stands with rear tires OFF the ground or simply place the vehicle on a shop lift and lift it up until all tires are off the ground, then crank it up, place transmission in drive and bring speed up to level where you were hearing the noise.
If you don't hear any noise while performing this test, it will eliminate everything on the REAR running gear thus eliminating all those parts.
Short of taking the front differential apart for inspection, your options are limited.
They do make electronic listening devices for finding noises where you put pickups at strategic locations under the vehicle and then go drive the vehicle and listen for the culprit noise. (See information below)

Cautions and Notes: wrote:

If you go the jack up the rear end route, be sure and chock both front wheels, forward and rearward real good on both sides before performing the test.
When you perform this test, it will set an ABS light on the dash, but it will go away once you drive it down the road a little with all four wheels rotating.
When you let off the throttle, be sure and slowly & gently brake the rear wheels to a slow stop before placing the transmission back in Park.
Do not think you can perform this kind of test on an 06 model since it has the traction control ABS system.

Wireless ChassisEAR Diagnostic Device Kit: https://www.steelmantools.com/wireless- ... 60635.html
SKU 60635, can be ordered direct or bought on Amazon.
The STEELMAN 60635 Wireless ChassisEAR is a unique automotive diagnostic device designed to pinpoint squeaks, rattles, vibrations, and other noises across a vehicle's engine, axles, and chassis.

WW.. as always, I appreciate your response, you're a great resource on this forum. thank you

WWDiesel · **Posted:** Thu Feb 13, 2020 11:45 am

Kind of ironic, I just got this email from a tool vendor this morning. I have no affiliation with them but have purchased several tools from them in the past. :shock:

This is a pretty good deal if you are needing this type of equipment to help pinpoint a strange noise in your vehicle.
Sale Price include free shipping.

ChassisEAR® Squeak & Rattle Finding Kit:> https://www.tooltopia.com/steelman-6600.aspx
Quickly pinpoints problems under Chassis, Fuel Injectors, Bearings, Gears & Suspension, Transmission, Differential/C.V. Joint.
Listen to six different under chassis locations in one road test
Clamp the six sensors on springs, torque rods, shocks, body mounts, brakes, dash assembly, door hinges, drive train, rear or front axle, transmission, transfer case, suspension, sway bars, tie rod ends, struts, axle hubs, ring & pinion bearings, mufflers, catalytic converter, 02 sensor, A/T case, oil pump, or even an un-torqued bolt

jeepsterkj · **Joined:** Mon Jun 11, 2018 7:38 am **Posts:** 52

Yes, I had a loud whirring noise from the front which started when I reached 20mph and it would get slightly louder and only change pitch a little after that. I knew it wasn't a worn clutch release bearing, as the noise didn't change when I dipped the clutch, nor did it change when I changed gear, or put it in 4x4...I had no idea what it was, but at one point I thought it was my gearbox on it's way out so I started looking for another gearbox...I was quoted £1950, including fitting, for a reconditioned box! And he would have expected mine in exchange for free! As it was still going into gear fine I eventually realised that wasn't the problem...Next suspect was the front prop shaft...I went to Propshaft Services, and the guy crawled under and checked the CV's at both ends...They were fine so it wasn't that.
Next I suspected a worn pinion bearing in the front diff and I was sure than was the problem until people kept suggesting I change the front hubs. I explained that if there had been any play in them it would not have passed the MOT. But then someone said they can still be noisy even when there is no play in them...And that is when I started looking for new hubs.
The strange thing was I could not hear any noise from the hubs outside with the windows wound down, only from the front somewhere, from inside...Which is why I didn't suspect them.
I got a pair of good quality, German made, ABS hubs for only £68 the pair on ebay. Fitting them was quite frankly a PITA as I had to make my own hub puller to get them off the driveshaft splines after struggling for hours without one, but afterwards...There was no noise! What a relief knowing it had been the hubs all along.

Habu_FPV · **Joined:** Fri May 19, 2017 8:28 pm **Posts:** 10

At around 50/55 mph I have a loud pulsing roar that not only can be heard but felt in the floorboard. It seems to be intermittently present at slower speeds and load/acceleration seem to change when and if I hear it. The pulsing seems to go away above 65mph but the loud roar is still there. It seems like it is coming from the front of the vehicle. However, my Jeep DOES NOT HAVE the forward drive shaft and front CV axles installed at this time and has new front wheel bearings. The noise is not dependent on engine speed (even off, coasting trans in N) and doesn’t change with tire pressure changes. The rear shaft to diff U joint was also replaced recently. The shaft to transmission U joint did not have any play and was not replaced. The U joint job did not change the roar either.

I know my rear upper control arm boomerang is worn-out, it will be replaced this week. Could this worn-out arm be causing a driveshaft u joint miss-alignment and that noise/vibration is just being felt in the front of the vehicle as the U Joint vibration transfers through the trans, engine and thus felt more up front? Motor mounts do not seem worn out.

I've seen several posts with similar symptoms that were solved by new front bearings, but mine are new. Is there a chance my new ones were manufactured wrong?

I’ll take a video of the noise when this very welcomed north Texas rains takes a break.

What do y’all think?

WWDiesel · **Posted:** Thu Sep 14, 2023 12:53 pm

Make sure it is not tire noise. Put it up on a rack (lift) and run up to speed where noise is usually heard and see if it is still there or it goes away.
(this will most likely trigger a ABS alarm, but it will go away once you drive it around on solid ground again)
If you still hear it, then it is in the driveline somewhere.
If you don't hear it, then it is most likely a bad tire?
While you got it up on a lift, you can spin the front tires/hubs by hand and listen and feel for a bad hub bearing and check all CV joints, driveshaft CV joints, and rear U joints.
:idea:

flman · **Posted:** Sat Feb 17, 2024 11:03 am

WWDiesel wrote:

Make sure it is not tire noise. Put it up on a rack (lift) and run up to speed where noise is usually heard and see if it is still there or it goes away.
(this will most likely trigger a ABS alarm, but it will go away once you drive it around on solid ground again)
If you still hear it, then it is in the driveline somewhere.
If you don't hear it, then it is most likely a bad tire?
While you got it up on a lift, you can spin the front tires/hubs by hand and listen and feel for a bad hub bearing and check all CV joints, driveshaft CV joints, and rear U joints.
:idea:

Yes, I replaced both front bearing one time on my libby, to find out the Bridgestone Revos were the problem, with a rotation front to back, noises changed. :roll:

flman · **Posted:** Mon Jul 13, 2026 8:33 am

So I recently replaced my rear differential, I knew it was bad as the seal let all the oil leak out. Was noisy under load, and quiet on coast. I went 4 wheeling in a lot of mud before I did this, and it became noisy all the time. So I thought I really did it in, stopped driving the Jeep until I could get it replaced. Replaced it, and still noisy, I think maybe front bearing, not sure how water tight they are, but the Jeep was deep in clay mud puddles, had to pull her out with a winch, so once I get going on my lift pump kit I am going to check all the following, this is what I learned from reading this entire thread.

1 Rotate Tires, the repair that costs nothing, that should always be the 1st thing.
2 Front, or rear wheel bearings
3 Transmission mount broken
4 Front transfer case driveshaft
5 Rear drive shaft
6 CV axles
7 Front., and rear differential

I was also thinking us 2006 owners that can't jack up and spin the tires for testing, remove the drive shaft, and spin with a drill?

BTW, what is a good place to get front wheel bearings? I was looking at Moog, pricey, but maybe worth it?

https://www.moog-suspension-parts.com/p ... berty_2006

WWDiesel · **Posted:** Mon Jul 13, 2026 11:55 am

Not 100% familiar with how the 06 will react if picked up on a lift/rack with all four tires off the ground and spun up to speed. (45-60 mph)
Doing this you can test/listen for noise location using a mechanics stethoscope while someone holds the speed steady.
Done this on plenty of vehicles in the past including my 05 Jeep Liberty, but it does not have the traction control of the 06's.
It simply set a ABS warning light along with a check engine light that went away as soon as I drove it for a little piece on the ground.

Can you turn the traction control off or unplug the ABS module power supply fuse long enough to test for bearing noises on a lift?

Another thought, if you are running any kind of tire other than highway tread; tire noise will really fool you and make you think you have a bearing going bad.
Remember, it is a unibody vehicle, so tire noise transmits very easily from the tire to inside the cabin.
That is why lifting all four tires off the ground and spinning them up to speed while listening with a Stethoscope will give you a true indication of where any bearing noise is coming from.

NOTE: FOUND THIS INFORMATION ONLINE: wrote:

You can safely unplug the ABS module or pull the ABS fuse to spin the tires/wheels up to speed on a rack without activating the traction control or causing damage. However, rather than unplugging the module's main wiring harness, it is highly recommended to simply pull the ABS/Traction Control fuse.

On the 06, it is fuse #14 in the "Junction Block" fuse panel on the left side of the dash according to the 06 factory service manual wiring diagrams.

flman · **Posted:** Mon Jul 13, 2026 3:12 pm

Thanks WW, you're the best. I wants to lock up the brakes on the 06, I'll have to give it a try with the fuse out.

I know all about the tires, they were the problem when I replaced front wheel bearings many moons ago.

03black · **Posted:** Mon Jul 13, 2026 7:38 pm

So what exactly is the noise? Is when you press on the go pedal or let off the go pedal? That will tell us if its the rear diff pinion bearings. Service manual has a great explanation of which one it can be (front or rear pinion bearing)
You could have swapped in a bad axle with bad pinion bearings or the ring gear backlash has worn out of tolerance. Replacing the bearings in the rear diff isn't necessarily difficult, but it is tedious. Only need a few specialized tools and there is lots of good videos on how to do it as well as the service manual.

WWDiesel · **Posted:** Mon Jul 13, 2026 11:31 pm

First he has got to pinpoint exactly were the noise is coming from, otherwise it is a guessing game. :lol:

If it were mine, I would get it on a rack, pull the ABS fuse, and disconnect the front driveshaft, spin up the rear axle and check for any bearing or gear noise in the rear differential using a mechanics stethoscope.
IF the rear is good/quiet.
I would reconnect the front driveshaft and then spin up the front wheels to speed and listed for any bearing or gear noise in the front differential.
If the front differential is ok, I would then listed to each of the front wheel hub bearing while they are spinning at speed.

Generally, in my experience, I found that front wheel bearings (hub bearings) when they go bad, the noise they make gets louder the faster you go, and putting stress on them side to side while going down the road makes the noise much worse.

And yes, MOOG hub bearings are one of the best!
:POPCORN:

flman · **Posted:** Tue Jul 14, 2026 1:08 pm

So pulling fuse 14 is not an option, once it's pulled the vehicle won't start. I tried starting it, putting it in gear and pulling the fuse and it shut right down. LOL what a nanny vehicle. If you do it with the fuse in, the ABS applies the brakes, and the traction control lights up.

So a little road test with my poor hearing I can swear its the right bearing, because it seems to get quieter on right turns while putting load on the left wheel. And dam, I threw out the bearings that I replaced for nothing years ago because I was moving last summer, they only had 50K on them, OE bearings. :banghead:

I was going to pull the transfer case prop shaft, but I took out one bolt, and differential fluid came pouring out behind it, how do you pull it, and drive it, if fluid comes out of the 8MM socket attachment bolts? Is it only a small amount, and put the bolts back in? Any how, have a minor amount of play near the CV joint on that prop shaft.

WWDiesel · **Posted:** Tue Jul 14, 2026 2:39 pm

Figured it out. After going back and looking at the wiring diagrams for the 06 and figuring out what all fuse #14 provides power to, it also supplies 12v power to the ECM, so that is why it shut the engine off when you pulled the fuse.
Next option would be to unplug the ABS module to disable it. That should have NO effect on engine running?

Pulling the front driveshaft between the transfer case and the front differential.
There should not be any oil in those CV joints, they are grease packed, and they both have a metal seal over the end of it to prevent leakage.
See enclosed picture.

You could completely remove the front driveshaft and drive the vehicle around without it. (Won't hurt a thing)
But that would not be of any help identifying the bearing noise, as all the hub bearings and differential bearings in the front axle will still be rotating even with the front driveshaft removed.

Real bummer on throwing out the perfectly good hub bearings! :banghead:

flman · **Posted:** Tue Jul 14, 2026 4:36 pm

[quote="WWDiesel"

Quote:

]Figured it out. After going back and looking at the wiring diagrams for the 06 and figuring out what all fuse #14 provides power to, it also supplies 12v power to the ECM, so that is why it shut the engine off when you pulled the fuse.
Next option would be to unplug the ABS module to disable it. That should have NO effect on engine running?

Where is that module.

Quote:

Pulling the front driveshaft between the transfer case and the front differential.
There should not be any oil in those CV joints, they are grease packed, and they both have a metal seal over the end of it to prevent leakage.
See enclosed picture.

The bolt on the differential side had axle lube come out, not sure how much would have come out, but I just put new fluid in, the shaft should just have the gray grease in it.

Quote:

You could completely remove the front driveshaft and drive the vehicle around without it. (Won't hurt a thing)

Of course, I would be okay with that, until I got a new shaft, or sent in the old one for rebuid.

Quote:

But that would not be of any help identifying the bearing noise, as all the hub bearings and differential bearings in the front axle will still be rotating even with the front driveshaft removed.

Yes, but it would eliminate the drive shaft as the culprit, which it may be, as it was the only part that had loose movement, I pulled the wheels on front, and spun the hubs, didn't hear no grinding, or feel any sticky points, like I have on bad ones in the past.

Quote:

Real bummer on throwing out the perfectly good hub bearings! :banghead:

[/quote]

I was thinking about throwing in the towel and selling it, but at this point I might as well keep her till she dies.

The CRD drive line noise thread

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