So, I'm back on the road again after 4 years of driving locally in a straight truck. I haven't bought a truck yet, I'm getting back in to this nice and easy. I'm pulling for Roadlink and learning intermodal the hard way. It certainly lives up to it's reputation.

But here's my question. This old Freightliner I'm driving is sure loud. My ears are ringing after I shut down every day. It's pretty fatiguing. I'm NOT expecting to drive this truck for very long, it's a short 9-speed and easy for me to get used to driving combination vehicles again. But it got me thinking about how high the sound pressure levels are in trucks. For kicks I downloaded a sound pressure meter app for my iphone. The inside cab volume was 100db.
I'm sure there are industry standards for this kind of thing. I find myself wearing ear plugs which do help, but not as much as you'd think.

Has anybody else ever looked into this kind of thing? How loud are trucks supposed to be?

 

Sounds like you might have a major exhaust leak there.... what kind of freightliner is it? Check the exhaust piping from the turbo back and look for any rust thru, loose clamps or spots with lots of black suit.

I had a loose clamp on my pipe to my cold air charger and I drove to Dallas from Chicago and didnt know (light load) till I got there and was sick as a dog. Went to the ER and had carbon-monoxide poisioning. Now every night I check all my pipes and make sure. It wasn't fun, and $18,000 later makes you a little paranoid LOL

My old FLD was a little noisy, but it was all mainly wind and engine hum. With a muffler, the exhaust was quiet, with the straight pipe tho it was quite load, but not enough to make my ears ring.

My new Pete is quiet as can be, and you can barley tell it's even running. And 0 noise from the exhaust.....till i put the Pitt mufflers on

 

I'm not too sure about the accuracy of an IPhone app to measure sound waves, but if it's even remotely close to that, that's a terrible work environment. 100 Decibels is actually damaging to your hearing, its like being at a rock concert all day every day.. I have an underbody mounted muffler on the international and its plenty quiet to talk to someone sitting in the passenger seat without hollering. Some people can put up with no mufflers and resonance in the cab, but I would rather hear the radio than the exhaust.

 

Good points guys. I'm not worried about the accuracy of the app. My ears can tell me how ridiculously loud it is, but I wanted some kind of a measurement to attach to it.

I don't know what kind of Freightliner it is. I'm not up on all of the models, but I'm going over to it today and I'll have a look.

The carbon monoxide is an issue which had not occurred to me, and I'll definitely keep aware of it. I drove this truck all last week and feel fine. It's just old, a little cramped, and the interior items (like speakers and dome lights) are limited in their functionality....and it's really freakn loud. I'll have a look at the pipes. I'm just glad to know other people's trucks aren't loud like this. The Columbia I started out on when I was flatbedding 5 years ago was obviously louder than a car, but I was trying to remember how loud it was in comparison to this truck. I'm glad to know this isn't normal.

Does anyone know what the normal Db levels inside a cab should be so I have a reference?

 

Found this chart on a website....

Some decibel ratings:
0 db Threshold of hearing
30 db Whisper
40 db Buzz of mosquito
50 db Normal conversation
70 db Vacuum cleaner
100 db Subway or power mower
120 db Rock concert
130 db Jackhammer or machine gun
150 db Nearby jet plane

Like I said, my new truck is very very quiet. So much in fact, that after starting it my first night in it, i had to get up to see if it was still running. Even the engine idles so smooth I couldn't feel it in the bunk!

You deff have some-type of an exhaust leak somewhere. Might even be a cracked manifold as the 12.7 detroits are known for them.

 

My 2000 Pete 379 is 70db's at cruise. We had to do a little work to get it that quiet. It doesn't take much of an exhaust leak to bring it up to 90 db's.

 

Thanks.
I did a cursory check of the pipe for any kind crack or rust hole but didn't see anything. It could be the manifold. I feel a little better about the carbon monoxide concern.

SpecialKay, what did you do to make your truck that quiet?

 

We dyna-matted the floor in the cab and sleeper and put some extra insulation between the upholstery and the the roof. We should have done the firewall also. There is cheaper alternatives out there, go talk to stereo guys for more info.

 

Keep wearing the ear plugs! Hearing loss is no fun at all, and an unfortunate occupational issue for truckers, amongst others who ride in vehicles.

 

100db is way to loud! Keep the ear plugs handy! After 20 years in auto body shops my ears ring ALL the time, it's no fun I actully take medicine dayly and can tell if I forget. Some times it's so bad I can't sleep from the ringing in my own damn head!