rhythmic noise while driving...

[TonyM]

'05 2WD XLT, 173k miles...

Truck was/is making a rhythmic noise that was especially noticeable when coasting or accelerating around and through 25mph. Needed new tires anyway - mine were cracking and the tread was poor with uneven wear - so I went and got new tires from Discount Tire. Noise persisted so I went to the dealer and they found that the left front hub needed replacing due to a bad bearing. Had them replace it but the tech noticed that while the noise diminished, it was still present. They say that the right hub/bearings are OK and couldn't find the source of the continuing rhythmic noise after having the truck at the shop for over a day. Checked the drive train, etc, so they say and couldn't find anything.

They chalk it up to tire noise as the tread is "pretty aggressive" according to them. My problem with this diagnosis is that I would think that brand new tires would create a noise that's constant, regardless of the tread, rather than a rhythmic noise. And, the noise was there before the new tires, though the new tread is similar to the old pattern...

At this service I also got new front brake pads - inside and out - and new rotors. Rhythmic noise was there before the brake and hub service, so I'm a bit stumped.

If it is truly tire noise, I can live with it, but I suspect something else. Tranny was serviced 10k miles ago, flushed with a new filter when I did the cam phasers, lifters, guides, chain, coils, plugs, cat converters, rear end, etc.

Any thoughts as to what I should have the dealership or a different shop look for?

 

[ChrisOIFdoc]

Rear differential

 

[docraymund]

It could be anything. Just go to another shop and have them check all under carriage parts pertaining to safety. If all are good, just wait for the noise to eventually manifest itself.

 

[TonyM]

Clutch pack in rear was replaced 5k miles ago, but i guess it could be something else in the rear differential. Will def take it to another shop soon. Any other thoughts as to what it could be are are welcome.

 

[ChrisOIFdoc]

Clutch pack in rear was replaced 5k miles ago, but i guess it could be something else in the rear differential. Will def take it to another shop soon. Any other thoughts as to what it could be are are welcome.

Pinion bearing is where I would start, but if you're confident in who ever did the work in the rear diff then move on to the axles, since your truck probably has rear independent suspension. That's about all I have to offer without being the one driving it.

 

[TonyM]

Travels finally allowed me to get this checked out independently...not good. This independent mechanic comes highly recommended and says the rhythmic noise if definitely coming from the rear diff - possibly the pinion as was suggested here by ChrisOIFdoc. The mechanic jacked it up and stethoscoped the rear end after checking all the bearings. He did this here at my house this morning with me helping and getting to listen. He says that since I had the clutch pack replaced in Feb by the dealer to go back to the dealer and see if they'll help me out as they were the last ones to work on the rear and this current issue started subsequent to the clutch pack being replaced and may be related. He also suggested that rebuilding or replacing these rear ends is very costly and I might want to prepare myself to get rid of the truck in case the dealer won't help offset costs, especially after they replaced the bearings and sent me on my way. Damn...

 

[ChrisOIFdoc]

Travels finally allowed me to get this checked out independently...not good. This independent mechanic comes highly recommended and says the rhythmic noise if definitely coming from the rear diff - possibly the pinion as was suggested here by ChrisOIFdoc. The mechanic jacked it up and stethoscoped the rear end after checking all the bearings. He did this here at my house this morning with me helping and getting to listen. He says that since I had the clutch pack replaced in Feb by the dealer to go back to the dealer and see if they'll help me out as they were the last ones to work on the rear and this current issue started subsequent to the clutch pack being replaced and may be related. He also suggested that rebuilding or replacing these rear ends is very costly and I might want to prepare myself to get rid of the truck in case the dealer won't help offset costs, especially after they replaced the bearings and sent me on my way. Damn...

The dealer may or may not work with you since it was 5k miles ago, but if they completely tore it down to replace the clutches I would fight em like a rabid dog to fix it under warranty. Parts don't cost that much, and the job is not that difficult. It could also be that the pinion nut is just loose. Did the mechanic check it by any chance? If the dealer tries to screw you, which they do on labor cost anyway, then find a good shop. Try 4x4 shops since they will have more experience generally with diffs. Knowledge is power, so read up on diffs before you have anyone bust into it. Good luck.

 

[TonyM]

Well...the good news is that it wasn't the rear diff, but the right rear bearings so two different sets of mechanics were incorrect in their diagnosis. The noise is no more. Unfortunately dealer wouldn't help me at all with the fact that they changed the front bearing and it was the rear that needed replacing to remove the rhythmic noise. Very frustrating.

Thanks for the input and guidance.

 

[ChrisOIFdoc]

Better a bearing than the diff. Glad it worked out.