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Need help! Bent axle shaft, bearing, or?


SB42

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Hi Everyone,

 

I apologize up front for the long post. My thought is that it’s best to include as much detailed info up front in an attempt to best describe the symptoms and background in order to get the best feedback from you all. I’ve learned so much from this forum so before I tackle this project I wanted to run it by everyone. I’m looking for valuable feedback so that I can hopefully resolve this myself in the first shot. Thanks in advance.

 

Long story short, oh wait, this is going to be rather long. I slid sideways into a residential style concrete curb. That afternoon we received quite a bit of snow in a short amount of time and the roads were slicker than I thought. I was making a left hand turn into a neighborhood at I’d say approx 15-20 mph. The front passenger side contacted the curb first which accelerated the rear end into the curb.

 

I continued on to my destination since it was less than 2 blocks away. Upon parking and getting out of the truck I could hear the tires deflating rather quickly. I took a quick look at everything and realized that I had trashed both passenger side wheels (17” GMC 6 spoke machined aluminum). The curb took about 6-8” of the bead right off the wheel. This is the first issue and at this point I was already livid with myself for such a careless mistake. Anyhow, I was able to get my truck into the garage and on to jack stands for the night so that I could salvage the tires. On a positive note (if there is one lol) the tires were not harmed – only a few scuffs, no chunks taken out of the side wall.

The next morning I started calling around to start pricing wheels. Not that I would order brand new ones from the dealer but I was astonished to find out the retail on this wheel is $691 each. WTF?!. I was able to locate 2 used OEM wheels at a shop in Denver and got them down to 145 each, so not terrible. I had the tires mounted on the used wheels and then got those on to the truck. First issue resolved.

 

Next, I head to the alignment shop. The shop brought everything back within spec and I was hoping all was well and fixed for less than $300. Second issue resolved. At this point I head home, with my lady following me, thinking all is well. Well, that would’ve been too good to be true.


On the way home everything seems good to go and the truck is riding nice and smooth and tracking just fine. No vibrations or anything of that nature. At this point I’m starting to relax as it seems like everything is back to par until……she calls me to tell me that she sees my rear passenger wheel “wobbling”! Great, just what I need. As I’m driving, I point my passenger side mirror all the way down and in, and lean over to the passenger side seat and can see it for myself; the rear wheel is “wobbling”.


I get home and start with basic troubleshooting. At this point I’m hoping that the shop sold me a bad wheel as that would be a simple fix. So, I switch the rear passenger wheel with the rear driver wheel. After a quick drive I get the same result. No vibration or anything but it still “wobbles”. Damn. I go ahead and switch it back and then I start to think about what it can be. Wheel bearing, axle flange, bent axle, etc.


At this point I’m torn, I’m thinking how can this be? I have a 2006 Sierra VMax. Which means, as most of you know, I have a ½ ton truck with a ¾ ton power train (14 bolt rear end, etc). I hit the curb solid but didn’t go over it nor was it very “violent”.

 

Monday comes and I figure I will call the dealer and talk to one of the service guys. I ended up having a pretty good conversation with this guy, almost 20 minutes or so. I walk him thru the situation and fill him in on the truck. He agrees that it’s hard to believe that I’ve bent my axle since I have the heavier duty power train, more specifically a 14 bolt rear end. At this point he relays that he’s thinking that it’s a wheel bearing, bent axle flange, or bent axle. We continue to talk and rule out a bent axle flange since the wheel
shouldn’t “wobble” if that were the case. It would just have a “lean” to it. He also tells me it would be $300 or so just to disassemble to see if the bearing was mangled. Damn. I ask, What would you do if this was your truck. He goes on to say that he would continue to drive it and see if the bearing ends up being
the culprit. I’ve replaced both the front hubs on this truck due to bad bearing so I am familiar with the sounds generated from a bad bearing so I see where he is coming from. At this point I’m hoping it’s a bearing as that is minor compared to the other options.


At this point, it’s been a couple weeks of around town driving and nothing has really changed. The only thing that I have heard since it happened was……when driving home at approx 45 mph I can sometimes hear/feel what seems to be a slight grinding, as in a bad bearing. But this only happens when slightly, and
I mean very slightly, turning to the right. When this happens I’m just following the road and not actually taking a “turn” to another street. When this first happened, I was hoping that it would get worse which would indicate that the bearing was bad. Not an easy fix, but better than an axle, right? This has not happened while driving straight, only when in the situation described above.


When I’ve had the truck in the air I’ve tested for play in the wheel, at both 12 and 6 and 9 and 3 positions. Just like you would on the front end and I don’t feel any real play.


Could it be a bad bearing where a few of the ball bearing where crushed therefore resulting in a “wobble”? I should also add, the wobble is not very big but certainly noticeable when looking. A picture is worth a thousand words so a video is even better right? I took a video to share with you guys so you can see it for yourselves, hopefully this is helpful.

 


A few details, some mentioned above some not:

-2006 GMC Sierra; Vortec Max package

-14 bolt rear end

-G80

-75K miles


What feedback do you guys out there have? At this point I fear that I bent the axle shaft. I don’t want to believe that but it seems that way. I am certainly not an expert and that’s why I’m here asking for assistance.


Any repairs that need to be done, I would like to do myself for a couple reasons. One, it saves me A LOT of money. When I did the hubs I was quoted 500-600 per and that was w/ OEM. I installed the Timken premium version for 225. Secondly, while it will likely take me longer than a mechanic I will have the peace of mind knowing it was done right, torque’d down right, and no short cuts taken.


What questions are out there that would help diagnose my problem?


Thanks again in advance for any of you that can help me thru this. I truly appreciate it.

Sam

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Has to be bent at the hub where it meets the axle. Don't take much these days to cause unbelievable damage. Stuff isn't as tough as it used to be.

 

I would think being bent that bad would cause gear oil to be slung all over the place on the inside of the wheel. You'll smell it a mile away if that's the case ... and you'll need all new rear brakes. If it's not leaking it must've just bent right next to the hub. Axle swap is pretty easy ... but I'd be examining everything in the rear diff during the swap. Like I said - it don't take much, so make sure nothing is cracked in the spider area - the gears themselves, the housing, and the pin.



EDIT damn double post ....

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Myself included ... but I can tell you from 600 miles south of you, it's bent. While your in there, change the bearing & seal. :)

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I'm near Denver (tbh I completely spaced ever updating my profile). We don't have Princess Auto around here but I will give the local stores a visit (O'Rielly's, Advanced Auto, Napa).

 

I'm pretty good with numbers so I will get my hands on a gauage and follow your instructions. Thanks again for your input.

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If you don't think it can be the axle, get your self a dial gauge, take the wheel and drum (assuming drum brake) off, and mount dial guage to the backing plate. Check the run out on the axle flange. Should be under 0.005". If more than that, axle is bent. Most likely bent right at the wheel bearing, outboard side of wheel bearing. Replace axle. I would also change the bearing and seal at the same time simply because you are at the point you would be at to change the bearing anyways(sort of like why you would change the timing chain when you take the timing cover off to fix an oil leak). I am surprised you do not feel a vibration. Also surprised the wheel alignment guy did not notice it when he mounted alignment head to that wheel and did the run out calibration(assuming alignment place used a 4 wheel alignment machine).

 

Have you driven the truck on wet roads yet? Reason I ask is that if the rear axle housing is bent as well, the truck will be a handful on wet roads. A 4 wheel alignment would have shown a bent housing if it was bent as well, but since they did not pick up the bent axle, I doubt they used a 4 wheel alignment machine.

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Definitely a bent axle. What some call hub or flange is all part of the axle anyway, so that will be new with the axle. Make sure to replace bearing because it will eventually fail. Have found many front bearing/hub assemblies to fail several hundred miles after a front end accident. Bearing rollers become slightly flat spotted from the impact and will eventually get noisy. Like earlier stated, don't forget the seal.

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Thanks for the input guys. :cheers:

 

Jsdirt, there isn’t any gear oil sprayed on the inside of the wheel. I can hear a small noise that happens when I come to a stop. I’m guessing it’s from things being out of wack down there with the hub and drum.

 

Doug_scott, I’m think that you’re right about the axle being bent at the wheel bearing. That makes sense that I would want to replace the bearing and the seal at the same time as I replace the axle shaft. The alignment shop (Firestone) didn’t say anything about it when they were finished. They did use a 4 wheel machine and I have the print out of the specs. Although, I wouldn’t be surprised if they spun the wheel a half spin and then mounted the head again and it would be out of tolerance. I have driven the truck on wet roads and in snow. It seems to handle just fine.

 

Where’s a good place to pick up a dial gauge? Don’t think that I’ve used one before. I will be pulling this apart in the next week.

 

Sam

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You have not entered a location in your profile, so I do not have any suggestions on where to purchase or rent a dial gauge. Never really understood why people don't enter location in profiles. If by change you happen to be in Canada, try Princess Auto. All you need to do is also get magnetic mount with flexible head to mount gauge to (should be able to get it from same place), mount gauge to backing plate, and mould the flex neck around to front face of axle. Zero the gauge by loosening the outer ring and rotating the scale around to put the zero line even with needle. Rotate axle and note highest and lowest number. Add the numbers together to get run out. If math is not your best, you can also rotate the axle to get the lowest number, then rotate outer ring and set it to zero on the pointer. Rotate axle again and now the run out is the max deflected number from zero. Pay attention to what the gauge is actually reporting, metric or sae.

 

It has been a long time since I did my last 4 wheel alignment (was actually right around the time we started doing 4 wheel alignments) so do not know if they still check run out on alignment head when mounting on wheel. If they don't there is no way you can get accurate numbers from the rear wheels, and it will make the thrust angle invalid as well.

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Hey Guys.

I agree with everything throughout the string. Thank you for all your input. It's what I needed in a situation like this. Sometime this week I plan to head over to a buddies place who has a heated garage. Based on all your feedback I know that I'm capable of tackling this myself however he is very into building 4x4 rigs so wouldn't want help from a guy like that.

 

I will update everyone once I have a chance to tackle this repair in the next week.

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You dont need to go through all that gauge checking, your axle is bent period. Pretty easy change out also.

 

While I agree axle is likely bent, I am also old school, prefer to know something before replacing parts. Then again, I already have the dial gauge and mounts.

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