Help with diagnosing rear end noise
12-02-2009, 07:42 AM
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Help with diagnosing rear end noise
I have had a persistent semi-annoying howl in the truck for the past couple of years and I was hoping someone could help me diagnose the probable cause of the noise.
The howl presents itself at speeds of ~20mph and up varying in pitch in relation to speed. The howl, I will describe as what you would imagine the classic hollywood sound effect for a stiff wind blowing oustide as you're inside of a spooky old vacant house.
Anyway, the noise is constant whether I turn left or right, accelerate or decelerate. There is no crunching, no grinding, and the noise is not even so loud to be noticeable to anyone that is not mechanically inclined. At first, I thought it was wheel bearings, but after I spoke to my uncle (a mechanic), he felt it was a rear end.
A little research turned up this link http://www.4x4now.com/gt0699.htm .
Does anyone agree that it could be the carrier bearings?
How could it be that the noise has stayed constant for years?
Let me throw some background information at you. Years ago (maybe 40-50K miles ago) I had a leaky axle seal like everyone else. At the time, I wasn't very knowledgable about how common the leaky axle seals were. I remember being told that there was oil leaking all over the inside of the tire/brakes, but I honestly do not recall having the seal replaced. Regardless, I have no leaking and a fully topped off diff right now.
Assuming I was driving around for a long time before my leaky seal was diagnosed and presumably fixed, what would be the first result of driving too long on low diff juice? Most likely the smoking gun, I would think.
I have well over 30K on the diff oil now, so a change is on the agenda for this weekend. I suppose while I am under there I should jack the rig up and spin the wheels to listen for the source of the noise as described in other threads.
Thoughts, comments please?
The howl presents itself at speeds of ~20mph and up varying in pitch in relation to speed. The howl, I will describe as what you would imagine the classic hollywood sound effect for a stiff wind blowing oustide as you're inside of a spooky old vacant house.
Anyway, the noise is constant whether I turn left or right, accelerate or decelerate. There is no crunching, no grinding, and the noise is not even so loud to be noticeable to anyone that is not mechanically inclined. At first, I thought it was wheel bearings, but after I spoke to my uncle (a mechanic), he felt it was a rear end.
A little research turned up this link http://www.4x4now.com/gt0699.htm .
Does anyone agree that it could be the carrier bearings?
How could it be that the noise has stayed constant for years?
Let me throw some background information at you. Years ago (maybe 40-50K miles ago) I had a leaky axle seal like everyone else. At the time, I wasn't very knowledgable about how common the leaky axle seals were. I remember being told that there was oil leaking all over the inside of the tire/brakes, but I honestly do not recall having the seal replaced. Regardless, I have no leaking and a fully topped off diff right now.
Assuming I was driving around for a long time before my leaky seal was diagnosed and presumably fixed, what would be the first result of driving too long on low diff juice? Most likely the smoking gun, I would think.
I have well over 30K on the diff oil now, so a change is on the agenda for this weekend. I suppose while I am under there I should jack the rig up and spin the wheels to listen for the source of the noise as described in other threads.
Thoughts, comments please?
12-02-2009, 01:40 PM
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Yeah, it's puzzling that the diffy could be damaged and begin to make noise and then not get any worse for at least three years now. I would assume that if a gear or bearing has been damaged it is only a matter of time before those things get progressively worse and then fail.
What ever it is, like I said before, is always present and noticeable above 15-20 mph, unaffected by accel/decel or turning left or right, and absolutley constant - meaning not a cyclical or repetetive noise - only changing pitch in correlation to vehicle speed. It also doesn't seem to get louder as the truck speeds up, just higher pitched until the wind noise cancels out the drivetrain noise.
It's merely an annoyance to me right now, but something I would love to fix if possible.
I have replaced the the spider gears in a Jeep before, but I have never attempted to remove a third member and work on it. Seems a lot more invloved. Especially with the e-locker.
I might try and tape one of my old smartphones under the truck and see if I can capture the noise.
What ever it is, like I said before, is always present and noticeable above 15-20 mph, unaffected by accel/decel or turning left or right, and absolutley constant - meaning not a cyclical or repetetive noise - only changing pitch in correlation to vehicle speed. It also doesn't seem to get louder as the truck speeds up, just higher pitched until the wind noise cancels out the drivetrain noise.
It's merely an annoyance to me right now, but something I would love to fix if possible.
I have replaced the the spider gears in a Jeep before, but I have never attempted to remove a third member and work on it. Seems a lot more invloved. Especially with the e-locker.
I might try and tape one of my old smartphones under the truck and see if I can capture the noise.
12-02-2009, 06:31 PM
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I've had to replace my rear axle seals twice now. Once because I was replacing my wheel bearings and realized the seals were leaking while they were in there, and the second time because the first guy screwed up or just did sloppy work. Either way, I also had to replace my rear brakes the first time. Honestly, I think the garage in West Southie is crooked.
Anyway, when my rear bearings were bad they made more of a whirring noise then a constant howling noise, so I doubt the noise you're describing is your bearings. I can't speak to the other parts you mentioned, however, because I haven't had to replace those...yet.
Anyway, when my rear bearings were bad they made more of a whirring noise then a constant howling noise, so I doubt the noise you're describing is your bearings. I can't speak to the other parts you mentioned, however, because I haven't had to replace those...yet.
12-02-2009, 08:38 PM
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I've had to replace my rear axle seals twice now. Once because I was replacing my wheel bearings and realized the seals were leaking while they were in there, and the second time because the first guy screwed up or just did sloppy work. Either way, I also had to replace my rear brakes the first time. Honestly, I think the garage in West Southie is crooked.
Anyway, when my rear bearings were bad they made more of a whirring noise then a constant howling noise, so I doubt the noise you're describing is your bearings. I can't speak to the other parts you mentioned, however, because I haven't had to replace those...yet.
Anyway, when my rear bearings were bad they made more of a whirring noise then a constant howling noise, so I doubt the noise you're describing is your bearings. I can't speak to the other parts you mentioned, however, because I haven't had to replace those...yet.
12-03-2009, 07:24 AM
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I'll bet you 10-1 odds it is the rear end. Had two 4runners now and what you describe is exactly what happenend to both of mine.
First one started at around 150k--they second one at 85K. They may howl but they will still go the distance. Its more annoying than anything else.
Its not the gears that go bad--its the bearings that get sloppy. The wheel bearing also dont go bad very often either. You may pull the axle and feel a lot of play in the bearing....BUT when it is bolted up it pulls itself tight against the axle housing flange
You can also try pulling the third member and tightning the adjusters a couple spots. Check out this website www.gearinstalls.com--they tell you how to do it.
Give that a try from the price of a tube of the Grey RTV and if it doesnt work send it to ZUK to get ZUKED
First one started at around 150k--they second one at 85K. They may howl but they will still go the distance. Its more annoying than anything else.
Its not the gears that go bad--its the bearings that get sloppy. The wheel bearing also dont go bad very often either. You may pull the axle and feel a lot of play in the bearing....BUT when it is bolted up it pulls itself tight against the axle housing flange
You can also try pulling the third member and tightning the adjusters a couple spots. Check out this website www.gearinstalls.com--they tell you how to do it.
Give that a try from the price of a tube of the Grey RTV and if it doesnt work send it to ZUK to get ZUKED
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12-03-2009, 10:42 PM
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Ok, here's an update. Since the weather was so nice here today, I decided to change my diff oil. I drained out only about 2.5 qts, and it was nasty looking. Seems it was low and dirty after all. When I checked it a couple of weeks ago, I stuck my finger in the fill hole and it came out wet. It's hard to tell with a fingertip, but it seemed to be filled up to the fill hole. I guess it wasn't. The Haynes manual says the locker diff takes 2.9 qts. Well, I got just under three full qts of Valvoline 80W-90 in there and less than 2.5 came out. When and how that missing pint disappeared is beyond me.
I took some pics of the grotesque black looking oil and the magnetic drain plug for your enjoyment. Only a couple of tiny tiny little fragments of metal in the silvery glop stuck to the drain plug.
I am glad to report that the whine has been greatly reduced with the oil change to the point of it being a non-issue for me. It is barely audible with the windows up and the radio off.
For now, I will be breathing a sigh of relief that my 3rd member is not fried. A little scorched, maybe, but not fried.
I took some pics of the grotesque black looking oil and the magnetic drain plug for your enjoyment. Only a couple of tiny tiny little fragments of metal in the silvery glop stuck to the drain plug.
I am glad to report that the whine has been greatly reduced with the oil change to the point of it being a non-issue for me. It is barely audible with the windows up and the radio off.
For now, I will be breathing a sigh of relief that my 3rd member is not fried. A little scorched, maybe, but not fried.
12-04-2009, 07:42 AM
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I am not at all against replacing the oil again if some feel that a synthetic or other oil can have restorative effects or do a better job at silencing the remaining howl/whine.
The guy down at the auto parts store suggested that I could have flushed the rear end with some ATF before filling it with lube. Seeing how filthy the oil was, I wish I had done that.
The guy down at the auto parts store suggested that I could have flushed the rear end with some ATF before filling it with lube. Seeing how filthy the oil was, I wish I had done that.
12-04-2009, 08:38 PM
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What I'd prefer to hear is a Yotatech guy like yourselves that have USED 80W-90 dino oil and a big-buck syntheitic or 140W and can SWEAR that the good stuff can actually quiet the gears versus the regular stuff.
I have no problem plunking down a few bucks on something that can solve a problem, but man it is tough trying to sort through the unscientific heresay written about oils and lubes.
After putting about 50 miles on the rig since yesterday I can say that the noise is down to an acceptable level, but STILL THERE. I'm still ineterested in exploring options. Anybody got a gut feeling about gear oil they want confirmed?
12-05-2009, 08:21 AM
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I had the same howling in my rear differential. The cause was the bearings wore out. I just replaced the whole 3rd member w/locker and she sounds like new.
12-07-2009, 11:53 AM
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had the same issue when I bought my truck. Turned out to be the ring and pinnion bearing. Shipped out just the rear differential in a rubbermaid tote to Zuk over @ www.gearinstalls.com and have never had a problem since. Sending it to him was cheaper than having a local drivetrain shop repair it.
12-07-2009, 12:17 PM
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had the same issue when I bought my truck. Turned out to be the ring and pinnion bearing. Shipped out just the rear differential in a rubbermaid tote to Zuk over @ www.gearinstalls.com and have never had a problem since. Sending it to him was cheaper than having a local drivetrain shop repair it.
12-07-2009, 01:00 PM
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X3--but I think I "polished" my gears and bearing with grinding dust. I think it is time for another one--what can I can say??
If you are not ready to have it rebuilt yet you might try using some thicker oil like--it may help a bit. But i do know that moly fills in the microscopic valleys in metal. But other than that this topic is more confusing than politics......
If you are not ready to have it rebuilt yet you might try using some thicker oil like--it may help a bit. But i do know that moly fills in the microscopic valleys in metal. But other than that this topic is more confusing than politics......
12-07-2009, 01:23 PM
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Well, I certainly don't need a new diff at this point. The oil change seems to have knocked down the majority of the noise. I am actually cruising around with the radio off again like I used to when the truck was new. Hearing that supercharger sing is like music to my ears.
Time will tell if the little remaining rear end noise will eventually drive me insane to the point of dropping some big bucks on a rebuilt 3rd. What's a typical Zuk rebuild cost if it is just some carrier bearings?
Time will tell if the little remaining rear end noise will eventually drive me insane to the point of dropping some big bucks on a rebuilt 3rd. What's a typical Zuk rebuild cost if it is just some carrier bearings?
12-07-2009, 01:26 PM
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I know a complete rebuild costs about ~1100-1300 depending on the build. Sans gears I am not sure--but if i were you i would get an LSD or something in there. They are great
