Making an old truck feel new

[GMC Guy]

Hey guys, so I just completed a long overdue LS swap on the ol' 74, plus a bunch of other small things I've been wanting to do. So far I'm satisfied and would never go back to an old school small block and three speed trans.

Now that it's back on the road and I'm driving it around, I've noticed that there are a lot of aspects to my 06 duramax that i wish were present on the 74, especially since the intent is to use it as a second vehicle. Cab noise, steering feel, and overall ride comfort.

Most notably, is the interior noises. The cab is undercoated inside and out, and mostly covered in FatMat, but i still have the rattles, squeaks, etc going on, mainly in the dash area.
I replaced all the weather stripping and had the vents rebuilt by Precision, but i still have quite a bit of wind noise and a REAL bad whistle through the passenger side vent... not happy at all after spending good money to have them rebuilt.

Moving on to steering feel. Everything is new (minus the box), and aligned. but the truck still likes to wonder around a bit... I'm thinking of upgrading to a CPP steering box.

Ride quality. shocks, springs, drop spindles, tires, everything is new. But for some reason my leveled 2500HD rides smoother? I really don't want to go air ride or coilovers for cost reasons, but now kinda regret it.

Any unwarranted noises drive me NUTS.. So i'm curious what you guys have done, or had to do, to make these squares feel newer. I'm tempted to gut the interior again, and start from scratch, insulating every piece.

[Mattchu60]

its probably not something you want to do since you had your vents rebuilt - but I used black silicone to seal my vents - no more wind noise through them.

I added the 2nd door seals that go on the door side and I think that helped a little as well. Otherwise I feel the same way - very hard to get these things quiet.

I noticed something - when I had my passenger door panel off and drove 100 miles - the noise from that door was very loud. I put the panel back on and it was quieter but I can still hear noise coming from the doors - not the windows or seams, but the doors themselves. Seems to me that the door shell itself is allowing air/noise in somewhere which is making quite a bit of wind noise. One thought was its coming in the rain vents at the bottom, or maybe through the door latch area. One thought was to put a full piece of dynamat over the inside door skin - havent tried that yet.

[GMC Guy]

Originally Posted by Mattchu60

its probably not something you want to do since you had your vents rebuilt - but I used black silicone to seal my vents - no more wind noise through them.

I added the 2nd door seals that go on the door side and I think that helped a little as well. Otherwise I feel the same way - very hard to get these things quiet.

I noticed something - when I had my passenger door panel off and drove 100 miles - the noise from that door was very loud. I put the panel back on and it was quieter but I can still hear noise coming from the doors - not the windows or seams, but the doors themselves. Seems to me that the door shell itself is allowing air/noise in somewhere which is making quite a bit of wind noise. One thought was its coming in the rain vents at the bottom, or maybe through the door latch area. One thought was to put a full piece of dynamat over the inside door skin - havent tried that yet.

yeah i thought about just siliconing them shut...maybe after I add a/c lol
i do think you're correct about the doors allowing a ton of air through. I've been meaning to order more insulation and cover everything i can, including the inside of the door panel itself.

[andrewpclayton]

my god that truck is beautiful.. nice work

[Keith Seymore]

Vents had wind noise when new. Not a lot you can do there within the original design, unless you want to start doing some extraordinary things like sealing them up or going to a one piece window.

Not sure what's going on with the wandering situation. My '87 drove like new, and was (one of, if not THE) the most comfortable vehicles I own, even after 30 years as a daily driver and a quarter million miles. The only thing I can suggest there is make sure the basics are covered: tight steering gear, run as much caster as you can muster. It could be tire related. I had a P235/75 15 on mine, so not a huge tire. Fat tires can grab the ruts in the road and throw you around a bit. Mine was cut coils in front and a leaf or two removed in the rear.

Regarding squeaks and rattles: I noticed when I had the interior stripped out how free it was from squeaks and rattles. It was still pretty tight after I re-installed everything but I could tell a difference. My suggestion is to use foam tape or insulate between the structural sheet metal and any added interior component. Wrap the door lock rods and door handle rods in foam anywhere that they could contact something else.

If it moves, insulate it. If it is not supposed to move, tighten it down.

- OR - you could always turn the radio up.



K

[GMC Guy]

Originally Posted by andrewpclayton

my god that truck is beautiful.. nice work

Thank you kindly. it’s by no means a show truck, but i can’t wait to get some paint on it

[GMC Guy]

double post.

[GMC Guy]

Originally Posted by Keith Seymore

If it moves, insulate it. If it is not supposed to move, tighten it down.

- OR - you could always turn the radio up.



K

thanks for the tips Keith. the vents didn't whistle prior to having them rebuilt, and that was with old dry rubber... go figure.
i guess the next mission will be to search and destroy unwanted noises. I'm lucky that the girlfriend is always eager to help pinpoint stuff like that while i drive haha
suspension set up is, 3 inch spindles, 2 inch springs front w/ bell tech drop shocks. maybe the springs are a little stiff for the ultra-light all aluminum LS?
rear is just a flip kit with drop shocks, gonna swap to extenders/stock length shocks soon.
tires are 245/45/20 front and 295/40/20 rear. I"ll check tire pressures and also take it back in for a re-alignment to get some more caster in there.

full stereo revamp is also in the works, so I probably will just be turning up the tunes more often than not haha

[hatzie]

The rag joint seems to have a different slightly looser feel compared to the Universal joint steering shafts in newer vehicles.

You could look into Borgeson either a complete shaft or components... Or a Jeep steering shaft if you're on a tighter budget... YJ series I believe. Make sure to keep something similar to the collapsibility of the original... it's one of the safety enhancements on the squares compared to the 60's rigs and it actually helps in an accident.

[GMC Guy]

Originally Posted by hatzie

The rag joint seems to have a different slightly looser feel compared to the Universal joint steering shafts in newer vehicles.

You could look into Borgeson either a complete shaft or components... Or a Jeep steering shaft if you're on a tighter budget... YJ series I believe. Make sure to keep something similar to the collapsibility of the original... it's one of the safety enhancements on the squares compared to the 60's rigs and it actually helps in an accident.

good point, I have replaced the rag joint recently, but i do very much want to upgrade the box and the shaft all together. Perhaps less assist on the steering so that the slightest input doesn't make it dance around.

[Dead Parrot]

Steering: make sure the screws at the base of the interior of the column are tight. My 75 with the OEM steering or OEM equiv replacements stays straight and is responsive to minor steering inputs. Easy to keep it straight in high crosswinds, which are common around here lately.

Ride quality: hard to tell what tires you have in the picts but low profile tires aren't always the best choice for ride comfort.

Cab noise: one area where the designed as luxury vehicles new trucks have a huge advantage. 2nd what Keith said.

[stanski]

Originally Posted by GMC Guy

good point, I have replaced the rag joint recently, but i do very much want to upgrade the box and the shaft all together. Perhaps less assist on the steering so that the slightest input doesn't make it dance around.

Check out my post yesterday regarding changing the power steering pump volume.

[TKCR]

I go crazy over noises and everything I have done, has helped a ton. I have heard that some people are getting wind noise after having their vents rebuilt. Mine are way better now. Also replaced all the other seals and door sweeps. Like Mattchu60, I got the upper door seal too, I just never installed them since the wind noise is better.
The other things I did, was while the cab was gutted to change interior color, I added Fat Mat to the floor and roof ( under the headliner). Fat Mat on the back wall behind the seat. Then the cardboard piece behind the seat, I put speaker carpet on it. Also lined the insides of the doors with Fat Mat.
On the cab floor: on top of the Fat Mat, I put the factory tar mat back down. I then used a foiled back jute padding. Then the new carpet, which had jute on the backside.
Behind the rear speakers, there is a space up between the rear panels. I put insulation in there.

[bennylava]

The interior squeaks and rattles have to be hunted down and fixed individually, unfortunately. But if you keep at it, you will eventually get them all. For more complete sound deadening, add a layer of closed cell foam, and then a layer of mass loaded vinyl on top of your Dynamat. Throwing down some dynamat and calling it done, just isn't the proper method. It will help, but to do the job right you need the foam and the vinyl. Most people won't do this because to fully sound dampen a vehicle the right way gets somewhat expensive. But it doesn't look like you mind spending money on the truck. Google sounddeadenershowdown, that guy pretty much has it figured out.

I'd check your wheel bearings, too. If you didn't replace them. And yeah the rag joint as someone mentioned. Also keep in mind that there is always the possibility that your steering box might need the adjustment screw tightened just a tad. I know you said the box is new, but you never know... could be things weren't done perfect wherever it was built/rebuilt. I really don't know how to tell when that adjustment is right where it needs to be, though.

But back to sound deadening, I'd get this for the doors:

http://cascadeaudio.com/car_noise_co...r_door_kit.htm

[Tash4]

TKCR has it as good as it will probably get. Seals behind door panels help some. Good luck.

[GMC Guy]

I did the 2 part sound deadening in the doors of my duramax and it made a huuuge difference. So I’m definitely planning on doing that with the 74. When i insulated the cab, many years ago, with fat mat, i also did the doors, but after years of monkeying inside them, I’ve had to remove some of it. Can’t wait to gut the interior and meticulously go through and insulate everything in hopes that it’ll be a nicer experience for low stereo volume situations haha Having the ability to tear the truck down and not have to hastily get it back together for work/school in the a.m. has made working on the truck muuuuch less stressful

[Richard2112]

A lot of great sound control advice in this thread. I am forever hunting squeaks and rattles.
There are things that I have discovered which I don't happily admit but ALL sheet metal transfers sound. If your hood flags in the wind, you'll hear it in the cab. If your front tires make a sound (they do) your metal wells will transfer it into the cab. After applying sound deadener as far up and under my dash as possible, I can still hear my cooling fan run. Sounds like the heater fan is on inside the cab.
One reason, a big one, that the newer trucks aren't as noisy is because there are some parts made of plastics which tend to deaden road noise. A lot.
My doors leak a lot of sound (other than just window rattles and air). My truck was very heavily under coated back in the day and still is (mostly), but I have discovered that if there is sheet metal, there is also sound transfer

[GMC Guy]

I’ve thought about undercoating the inner fenders on the tire side.
Also, i added some “bulb” style weather stripping from the common parts store to the upper door area where the factory installed it. seems to have helped a little bit. the biggest gripe is the air leak in the passenger vent window right at the top...

[SKT]

.

Interesting thread.

Looking forward to seeing more responses.

.

[bennylava]

Originally Posted by GMC Guy

I did the 2 part sound deadening in the doors of my duramax and it made a huuuge difference.

Which 2 parts did you do? For me, I was thinking of the Dynamat inside the doors, and then that Cascade brand liner that I linked. Should be a knockout punch against sound from the doors. Not really enough room in there to do much more than that anyway.

[GMC Guy]

Originally Posted by bennylava

Which 2 parts did you do? For me, I was thinking of the Dynamat inside the doors, and then that Cascade brand liner that I linked. Should be a knockout punch against sound from the doors. Not really enough room in there to do much more than that anyway.

i used this stuff http://www.raamaudio.com
The owner did a very detailed write up on one of the diesel sites that explained where and why you need to sound deaden. The foam needs to cover everything it possibley can, but the mass loaded vinyl doesn’t. only in larger flat panels, but we all know we can’t resist the urge to put that stuff everywhere haha Hey if it’s worth doing it’s worth over doing right?

[TKCR]

I have heard good stuff about this product. I wish I would have found it before all the work I did on my truck. Another member used it on his build, N2TRUX: it starts on page 20 Post #483

http://67-72chevytrucks.com/vboard/s...705824&page=20

And here's a video I found on youtube:
https://www.youtube.com/watch?v=9gOpldzfJBo

[1980c10]

I've battled the vent noise many times. I've rebuilt them myself twice. I eventually swapped them with the newer style from a late '80s suburban and new precision seals in those as well. It was a big improvement. Dynomat inside the door on the outer door skin was a really nice improvement. As far as the steering; the adjusting screw on the steering box is critical. Too loose and the steering feels loose. Too tight and the wheel won't return to center. Trial and error worked for me getting this set. I'm sure their is a more proper procedure for this...

[bennylava]

Originally Posted by 1980c10

As far as the steering; the adjusting screw on the steering box is critical. Too loose and the steering feels loose. Too tight and the wheel won't return to center. Trial and error worked for me getting this set. I'm sure their is a more proper procedure for this...

Yeah and I really would question the setting even on a new one. Unless maybe it was one of those top tier ones like Redhead. Even then I'd have to ask them if they dial it in perfectly, or leave it up to the customer. I've heard you only turn it 1/4 of a turn at a time. Then you go drive the truck and test it. But this may be only on old boxes that have been on the truck for who knows how long. No idea what to do on a new box to check and see if its properly adjusted.

[Gregski]

I am fixated on that engine bay, I think I've been staring at it for hours, that is poetry under the hood! Incredible job mate! Wow!