Howling from rear end, increases with speed. Pinion bearing?

[legendaryandrew]

My research indicates the pinion bearing wear, but what can I do to make sure it is infact the pinion? Noise started after a trip up the mountains to go shooting. No wheeling involved, just dirt roads. My friend heard the noise first.

Not sure if relevant, but the truck is lifted 6" (3.5" in back, HD truck already higher in rear than front). The rear has tapered blocks, to help correct for drive shaft angle.

Second part of this post, I need advice on wether or not I should regear. I'm new to this expedition/offroad thing, but I figured while I was in there fixing whatever issue I'm having, I may as well add gears and traction devices, but a friend of mine who has several wheeling rigs (k5 with rockwells, DMAX SAS with 44", etc....) said I shouldn't worry about gears. The 8.1l in my truck has a Blackbear tune on it, and for a 7k lb truck, is downright fast. I don't plan to do anything too technical, but I figured with the addition of 35" tires, it wouldn't hurt. It has factory 3.73's on it now, and at 60mph, sits right around 1800-2000rpm. Not sure where the sweet spot is for the 8.1 either, so that could effect my decision. Anyway, thanks for any and all pertinent advice

 

[82fb]

I would think you are on the right track with pinion bearing. as far as gearing goes, my 8.1 has 4.10's with 33's. I tow 10k a lot and it is great. If I did not tow much, I would rather have 3.73 gears. The 8.1 has so much grunt, I think you will be fine 3.73 and 35's.

If you find that gear work is needed, I would probably find a junkyard axle with the g80 code. Gets you a "locker" if you don't already have one. Or if money is no object, an ARB or Detroit are great.

 

[rayra]

could be 'just' a wheel bearing.


here's your pinion test -

http://www.youtube.com/watch?v=LzOyWNyEcZs


It would be a worthwhile exercise to change all three bearing sets and seals at the same time.

 

[402xjeeper]

Usually pinion bearing, the tapered block may not be correct, on anon cv shafts the angles should be equal under load at both ends of the shaft. Also a tapered block reduces the fluid level at the fill hole by tilting the diff, and can effect pinion bearing life. Any driveline vibration can make this worse. I used to manage a 4x4 store and have run into similar problems on lifted Gm trucks, a very hard diagnosis because usually there are multiple things going on., don't ignore the t case and front driveline in your search, grab and turn the front driveline while parked, if it will not turn it may not be disengaged at the t case or front axle disconnect, causing it to spin. It sounds crazy, but noise and vibration anywhere in the drive train travels , and pickups have less noise control from the rear. All that said, it is most likely the rearend, I would do everything at once, mixing new and used parts in a diff is harder than setting up new parts. A low fill level can take out wheel bearings as well.

 

[jonpaul]

I recently acquired an 02 Yukon XL 8.1, 4.10, with 33K miles. Picked it up from an older couple moving into assisted living. They bought new and used only to tow 30' travel trailer on family vacations. It was serviced at the dealer once a year for 14 years. From day 1, I've noticed a howling noise especially loud between 55-65. Doesn't matter if I'm accelerating or decelerating, in D or briefly shifted to N. The noise doesn't change. Below 50 it's unnoticeable.

I've scoured many different sites, forums, service bulletins. Did you ever resolve your issue?

 

[Johnston]

I recently acquired an 02 Yukon XL 8.1, 4.10, with 33K miles. Picked it up from an older couple moving into assisted living. They bought new and used only to tow 30' travel trailer on family vacations. It was serviced at the dealer once a year for 14 years. From day 1, I've noticed a howling noise especially loud between 55-65. Doesn't matter if I'm accelerating or decelerating, in D or briefly shifted to N. The noise doesn't change. Below 50 it's unnoticeable.

I've scoured many different sites, forums, service bulletins. Did you ever resolve your issue?

If you have the aluminum driveshaft it is pretty noisy. Every time my mechanic rides with me he thinks the rear end is going out. Had Six States (rear axle shop) look at it and said everything is fine just driveshaft noise.

 

[jonpaul]

Even with a vibration?

 

[Johnston]

Sorry jonpaul. I didn't see where you mentioned a vibration. I just have that howling noise especially in the fast lane on the freeway with the concrete divider amplifying the noise.

 

[GmTech14]

just to throw something in no ones stated so far, if it started AFTER you did the lift, I would be checking U-joints. (actually i would be checking either way, easy to check) even though you have a pinion shim to adjust angle, it still isnt 100% identical to what it was before. after 1000's of miles they get a "wear groove" and when you change the angle slightly it would be getting out of that previous pattern.

to check take out driveshaft and move the U-joint side to side and up and down. it should move freely without any spots it catches and should not be stiff.

edit: just realized this thread is long dead but info may apply to others

 

[jonpaul]

just to throw something in no ones stated so far, if it started AFTER you did the lift, I would be checking U-joints. (actually i would be checking either way, easy to check) even though you have a pinion shim to adjust angle, it still isnt 100% identical to what it was before. after 1000's of miles they get a "wear groove" and when you change the angle slightly it would be getting out of that previous pattern.

to check take out driveshaft and move the U-joint side to side and up and down. it should move freely without any spots it catches and should not be stiff.

edit: just realized this thread is long dead but info may apply to others

No lift on my 02 Yukon XL 8.1, 4.10s on stock 245 16's. I bought it last month (March 2016) with only 32K miles. Sat in a garage most of its life. I thought the same and u-joints changed in both shafts. No difference. Between 55-70 it sounds like a bad wheel bearing but can feel a vibration in the seat accelerating or decelerating. Have not checked the rear outer axle bearings. Will post findings. Any feedback welcomed.

 

[Buliwyf]

I recently acquired an 02 Yukon XL 8.1, 4.10, with 33K miles. Picked it up from an older couple moving into assisted living. They bought new and used only to tow 30' travel trailer on family vacations. It was serviced at the dealer once a year for 14 years. From day 1, I've noticed a howling noise especially loud between 55-65. Doesn't matter if I'm accelerating or decelerating, in D or briefly shifted to N. The noise doesn't change. Below 50 it's unnoticeable.

I've scoured many different sites, forums, service bulletins. Did you ever resolve your issue?

Does it go away at 70mph? If it does, it's just road resonance.

Could be the tires.

 

[jonpaul]

Does it go away at 70mph? If it does, it's just road resonance.

Could be the tires.

Not completely. Tire balance/check is next on the list.

 

[fiddypal]

I was getting bad vibration on my silverado 1500 at highway speeds, got the wheels balanced and a couple were out of wack, thing drives like a dream now!

 

[jonpaul]

I was getting bad vibration on my silverado 1500 at highway speeds, got the wheels balanced and a couple were out of wack, thing drives like a dream now!

My folks owned a tire shop which I worked in while growing up. I drove a lot of cars (diagnosing vibrations, sounds, etc). I don't ever remember a howling + vibration being the result of tires out of balance or bad.

But it would be the cheapest thing to do. The tires are OEM Bridgestones from 2002. May be the exact culprit.

 

[jonpaul]

Re: Howling

Update: pulled the diff covers, no abnormal wear. No pitting on axle bearings or races (again only 33K miles). Put back together and had rear tires checked and found them to be out of balance. Drove today on interstate same loud howling noise and vibration (if it was faint I wouldn't mess with). Moving to the front next and plan to check the bearing hub assemblies.

Feedback welcomed.