Duramax noise - Montana Owners Club

Legend · 07-06-2009, 08:40 AM

I am towing my 2006 3400RL with a 2008 Chevy 2500HD D/A. My last trip climbing most grades there will be a loud siren-like whinnying noise that sounds like it is coming from right behind the center of the firewall. The loudness follows the amount you are depressing the accelerator. The GM dealer said this is normal Turbo noise. Also during this trip the transmission temp spike to 228 at times and ran 195-210 the others.

Has anyone had this same sound and what should the temp run fully loaded during hilly Interstate travel at 65MPH.

Thanks for any help.

HughM · 07-06-2009, 10:09 AM

Yep, you bought a turbo diesel. That is the noise you hear near the firewall--the turbo.
Further forward would be the fan coming on and that's loud also. I was told by a GM diesel mechanic that the transmission shouldn't get higher than the coolant temp. 195-210 is not a problem at all.
The temp at a fully loaded hilly interstate at 65mph. I would suggest around 60-62 and your temp will go down if its a looong hill.
228 and I would diffently back off that throttle and let it cold down 10-15 degrees.
Have you weighed you fully loaded trailer? A CAT scale will tell you a lot of infomation for $8.
Hugh

Tom S. · 07-06-2009, 10:31 AM

Temps are normal, but are you sure the noise wasn't from the cooling fan kicking on? Maybe I'm deaf, but I've never heard any turbo noise with mine.

BTW: don't believe the water temp gauge. It has been widely reported that GM has programmed it to show lower temps than actual, and I tend to believe it is true. I have an engine oil temp gauge and at one point, it was well over 300 degrees (102 degrees outside going up a mountain) while the water temp said 220 - which is B.S.

TLightning · 07-06-2009, 10:58 AM

I've never heard that noise.

Re temps, if all else fails, check the manual...normal range is 100 to 265. At about 275, you will get a note on the DIC that will say "TRANS HOT IDLE ENGINE" and a chime will sound.

KathyandDave · 07-06-2009, 12:21 PM

Have you been spying on us? We've had the problem that the transmission temperature, as indicated on the DIC, gets up above 80 degrees C (179 F) and the Allison won't upshift. It tries to soldier on in a lower gear at high revs. I have to pull over and let it cool down with the engine running. We never exceed 100kph (62mph). I let the speed drop on hills to keep the revs below 3 grand-ish. The problem has occurred on long hills (north of Superior) and local roads, equally. It seems to be related to down-shifting in tow-haul mode. This problem is happening more frequently, recently on local roads at low speeds, so I've talked with the GM dealer and they're going to take it in to look at codes. The service guy there says that the truck should pull our trailer with ease. The actual trailer weight, 15,000lbs, is within the limits for the truck, as stated in the manual.

mcgiver2 · 07-06-2009, 12:40 PM

hey ever one it sounds to me its the Cooling Fan i live in south Louisiana and evening in the warm mornings my cooling fan come on..... and my ford use to do that noise when i put a load and start climbing hills............... hope ever one had a great weekend......Allen

Trailer Trash 2 · 07-06-2009, 12:52 PM

Legond you stated on a pull you hear a niose, you might want to check these items.
If you TV is chiped, it COULD BE the waist gate dumping and the spring is weak, allowing it to open, or a crack in the Y pipe this can be checked by checking your boost, on my old TV it would not go over 12 or 15 pounds of boost, when it used to get 21/22 check you fittings to the intercooler for air leaks. these are some of the things that turned up for my old Ford it did the same when under a heavy load or pull up a hill.

Legend · 07-06-2009, 01:12 PM

If it is the cooling fan, it is the loudest one I have ever heard. It will drown out the radio. It really makes you think something is going to blow. It doesn't seem to be RPM related, because it will happen anywhere between 1800 and 3000 RPM.

Never hear it when I am not towing. It also doesn't seem to affect the shifting of the transmission.

Thanks for all the replies.

Bill-N-Donna · 07-06-2009, 01:56 PM

Quote:

quote:Originally posted by Legend

I am towing my 2006 3400RL with a 2008 Chevy 2500HD D/A. My last trip climbing most grades there will be a loud siren-like whinnying noise that sounds like it is coming from right behind the center of the firewall. The loudness follows the amount you are depressing the accelerator. The GM dealer said this is normal Turbo noise. Also during this trip the transmission temp spike to 228 at times and ran 195-210 the others.

Has anyone had this same sound and what should the temp run fully loaded during hilly Interstate travel at 65MPH.

Thanks for any help.

I heard that siren sounding noise in my F-350 Turbo the same day I lost the oil cooler. It’s my thinking that it had a leak and the extra coolant in the system was causing the loud siren sound as it was going through the motor and into the exhaust. I was towing at speeds around 55 MPH when I noticed it the most. Not long after that when I was at the campground I was having a lot of white smoke coming out the exhaust. I don’t know that you have the same problem but you might take a look at your coolant level and keep a check on it. I doubt that it would be a cooling fan by the sound you describe and the experience I had.

SlickWillie · 07-06-2009, 02:44 PM

If it is the turbo, I would think something is wrong. I also believe you are hearing the fan engage. When the one on the GMC engages, it sounds like a jet engine.

As far as tranny temps, you might go on diesel place and take a look. There is a guy over there (MikeL I believe)that builds a good aftermarket tranny cooler.

Ozzie · 07-06-2009, 03:17 PM

Mike really knows his stuff with trannies - one of the best around.
I am a mod at a diesel forum too, and have learned a ton from those boys. They have loads of knowledge and love to help others as a rule.

I personally have gauges installed in mine as I want to know how hard I'm working things. I love to hear the turbo work as long as everything is in spec.

Bill-N-Donna · 07-06-2009, 03:31 PM

So, I take it then that the siren sound we’ve been talking about could be and sometimes is a normal sound whenever the turbo is being worked really hard, is that correct?

If that sound I’ve heard is the turbo fan it is definitely a loud one.

Ozzie · 07-06-2009, 04:08 PM

I don't know if this sound you're describing is something different than it has been in the past. That would be key for me.
This is one of the reasons I put in the boost and exhaust temp gauges.

capn chris · 07-07-2009, 04:45 AM

I, too, vote for the electric fan kicking in on long uphill grades. Makes quite a whine. When you crest the hill it slows and goes off. Happens on my Ford, sometimes.

padredw · 07-07-2009, 10:41 AM

The first time I heard this "siren sound", I became really concerned. It has only happened 2 or 3 times in the year that we have had our Duramax/Allison (2500 - 2008 model). This is the second Duramax we have owned and never heard it on the previous model.

I had reached the conclusion as expressed by several above, but seeing this on the Forum is an additional assurance that nothing is seriously wrong.

But, Boy! does it get your attention when you are in a strain.

Art-n-Marge · 07-07-2009, 11:07 AM

Two wierd noises can come from my turbo diesel especially when towing. A whine of the turbo; just monitor the gauge, and an arbitrary fan noise that turns on to help cool things down when we demand a lot of the truck, like on uphills, while towing and we are mashing the accelerator.

Think of it as "Tim the Toolman" noises.

KathyandDave · 07-09-2009, 03:28 PM

I guess our problem is different. The noise starts AFTER the hill.

Bill-N-Donna · 07-10-2009, 01:37 AM

When I was hearing the siren sounding noise it wasn’t just going up hill. I would sometimes hear it going down as well. It would also come and go but still it was mostly noticeable when under a strain and going up hill.

Trailer Trash 2 · 07-10-2009, 05:06 AM

Well I still say it's the waist gate opening on a hard pull with high boost. or the gate isn't closing all the way due to a weak spring.

Devildog · 07-10-2009, 08:44 AM

When pulling with my 2001 Duramax, my cooling fan will usually come in about 3/4 way up the hill and over the top. Sensors are not only for the engine, but a temp sensor on the transmission cooler also that notifies the fan clutch to start pulling more air. First time I heard it, sounded like a tornado under the hood, but got used to it soon after.

Turbo whine or whistle. when turbo boosts up past about 15 lbs, I get the whistle, and it comes from air flow. Can be a wonderful sound if you're expecting it, or it could be annoying. But three years ago, I had a different sound when turbo came on, and it sounded like a large air pump underneath the hood, and noticed that boost jumped too fast. upon arriving home, I checked the engine bay and discovered that the passenger side pipe from the turbo back to the engie, and been pushed up against the fuel pump when I was changing my fuel filter and had tightened everything up hose wise on the engines. It had actually rubbed a hole through the turbo pipe. I repaired it with two muffler clamps, some sealant and an aluminum piece to cover the hole, held on by the clamps. No more issues with turbo, and now have 167,000 miles on it.

Good luck with your diagnosis

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