New (Bad?) Noise in my 2007 6.0L Diesel

Velogeo · 05-08-2010, 07:22 AM

I'm starting day 4 of my around the US trek. Not a good time to hear something new. I'm getting a new noise which I don't like. At highway speeds when there is no load on the engine I'm get a loud, low rumble. You as much feel it in the seat of your pants as hear it. I can make it go away by giving the engine a little throtle. Mostly I'm getting it coasting down small hills (I'm in Iowa) and the occasional flat section. I don't get it while climbing or doing any compression braking, just when there is no load. The ScanGuage LOD reading tends to be between 10 and 15, give or take. I checked under the hood and pulled the doghouse and don't see anything obvious like spewing fluids or loose plumbing for the turbo. I may or may not be hearing other minor noises. Problem is I've lost most of my high frequency hearing (Party on, Garth) so diagnosing these things can be a pain. I think the engine always sounds rougher when I get away from Washington states mandated B5 biodiesel anyway.

Anyone have any ideas? This is going to require a stop at a dealer, I think. Not something I'm looking forward to. At least I'm getting closer to whatever dealer SMB Huntington uses.

Peter

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EMrider · 05-08-2010, 09:26 AM

Quote:

Originally Posted by Velogeo

I'm starting day 4 of my around the US trek. Not a good time to hear something new. I'm getting a new noise which I don't like. At highway speeds when there is no load on the engine I'm get a loud, low rumble. You as much feel it in the seat of your pants as hear it. I can make it go away by giving the engine a little throtle. Mostly I'm getting it coasting down small hills (I'm in Iowa) and the occasional flat section. I don't get it while climbing or doing any compression braking, just when there is no load. The ScanGuage LOD reading tends to be between 10 and 15, give or take. I checked under the hood and pulled the doghouse and don't see anything obvious like spewing fluids or loose plumbing for the turbo. I may or may not be hearing other minor noises. Problem is I've lost most of my high frequency hearing (Party on, Garth) so diagnosing these things can be a pain. I think the engine always sounds rougher when I get away from Washington states mandated B5 biodiesel anyway.

Anyone have any ideas? This is going to require a stop at a dealer, I think. Not something I'm looking forward to. At least I'm getting closer to whatever dealer SMB Huntington uses.

Peter

-- sent from my Droid using Tapatalk

Always hard to say with stuff like this, but I'd guess that your drive line u-joint is worn and creating the noise/sensation you describe. Mine went bad at about 20k with very similar symptoms to what you are experiencing. Mine failed because I didn't regularly grease the joint.

IF so, good news is that it is not a complex or expensive fix. Cost me something like $250-300. But bad news is that it should be looked at asap because a u-joint failure at highway speed is a big safety risk. Good luck and hope this does not cause too much of a delay.

Rob

saline · 05-09-2010, 01:14 PM

X2 on the U-joint. I had a very similar experience at 32k miles.

UJOINT · 05-09-2010, 07:12 PM

I agree, sounds like a driveline issue. Could it be in 4wd? Check that, maybe even isolate the front driveshaft by removing it & driving.... just some ideas.

Railvan · 05-09-2010, 08:18 PM

It sounds exactly like what my van did when the front U-joint was going bad.

Brian Rutherford

Aldercrest · 05-12-2010, 11:19 PM

I have a similar vibration in my 2002 7.3 with 70,000 miles. It's a weird rattle under the dash right around 1,500 to 1,600 RPM. Speed up or slow down and it goes away.

For clarification, by front u-joint do you mean the front u-joint on the rear driveline? How do you check something like this? Everything is tight on my rig aft of the transfer case. However, there is a little play in the front driveline at the transfer case. I don't see how this would create vibration when in 2wd with hubs unlocked, so I must be missing something. Any ideas?

Velogeo · 05-15-2010, 06:32 PM

Rob, I have to thank you (and to some extent having poor impulse control) for saving me a lot of money and trouble. I was speeding along I-80 in Illinois when I saw the JC Whitney Outlet store (we'll ignore the humor in the fact that I needed some 12v outlets from the outlet store) so I pulled off. While I was browsing I got the little ding on my phone saying I had an e-mail indicating a reply on the forum. As soon as I read it I knew that's what it was. Took a look to confirm it and immediately started looking for a place to fix them for me. Turns out every shop in the area closes for the weekend at lunch on Saturday except Sears Automotive. It was late enough in the day that I got a hotel room and had them fix it Sunday morning. Fix it they did, though. Thank God. The bearings in the rear most u-joint were totally shot by the time I pulled into Sears that afternoon and were screaming something fierce. I wouldn't have made it more than 10 miles down the highway.

Actually, I guess it's an endorsement for having internet and forum access on your phone as well.

Thanks,

Pete

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EMrider · 05-16-2010, 09:23 PM

Quote:

Originally Posted by Velogeo

Rob, I have to thank you (and to some extent having poor impulse control) for saving me a lot of money and trouble. I was speeding along I-80 in Illinois when I saw the JC Whitney Outlet store (we'll ignore the humor in the fact that I needed some 12v outlets from the outlet store) so I pulled off. While I was browsing I got the little ding on my phone saying I had an e-mail indicating a reply on the forum. As soon as I read it I knew that's what it was. Took a look to confirm it and immediately started looking for a place to fix them for me. Turns out every shop in the area closes for the weekend at lunch on Saturday except Sears Automotive. It was late enough in the day that I got a hotel room and had them fix it Sunday morning. Fix it they did, though. Thank God. The bearings in the rear most u-joint were totally shot by the time I pulled into Sears that afternoon and were screaming something fierce. I wouldn't have made it more than 10 miles down the highway.

Actually, I guess it's an endorsement for having internet and forum access on your phone as well.

Thanks,

Pete

-- sent from my Droid using Tapatalk

Glad you got it fixed safely and without much drama or lost time from the roadtrip.
R

Railvan · 05-17-2010, 10:40 AM

Quote:

Originally Posted by Aldercrest

For clarification, by front u-joint do you mean the front u-joint on the rear driveline?

Yes, the front U joint on rear driveshaft. It got dry and stiff and was "hammering" on the yoke of the transfer case, which ended up being replaced too since it would no longer tightly fit the new U joint.

Brian Rutherford

gregsmith212 · 05-28-2010, 03:22 PM

Hey, I just had to replace both u-joints in my 2006 6.0 with 34000 miles. It started with a noise the sounded like something that was loose in the refrigerator and then moved to a low rumble behind the doghouse, and would go away when you added some gas.

After looking on the forum I went straight to the problem and $50.00 in parts I'm back on the road.

Thanks