Hi everyone, I have a 06 soft top TJ. I bought it a couple years ago with 110k miles and it needed a ton of work. One of the issues was road noise and wind noise. Everyone told me a TJ would be loud, Coming from an older convertible MINI, I'd assumed it would be similar. I didn't think it would actually be difficult to have a conversation at 80 mph. After some work, I've pretty much solved it though so I wanted to share on here!
The Top
The soft top that came with my Jeep was a SmittyBilt and it sucked. There was also missing hardware. First thing I did was replace the missing hardware and replaced the old top with a Bestop Twill Top. This upgrade got rid of the flapping sound at lower speeds, but it was STILL loud on the highway. I realized that majority of the sound from the soft top came from the constant up and down oscillations of the top cancelling out sounds in the cabin which made it difficult to hear my passengers and would drown out the sound system. That "boomy" low frequency sound from the top is what I'm referring to. Of course, this will always be present in any convertible, but I figured I can reduce the intensity though by reinforcing the top.
It worked, and this is my set up:
There are definitely ways to make it prettier but it's functional. I bought this mattress topper and then trimmed it so that when folded, it would line the area of the top from the sound bar to the header. The memory foam compresses and conforms to the shape of the top and braces it. To cover it up, I used this. To hold the mattress topper up and compress it, I used two PVC "top props". See this for more info. I did the same but used two! The foam mattress topper is just the right size, so I can shove it behind the backseat when the top is down. This probably made the biggest difference at high speeds or when it's windy out, and it's not very inconvenient to remove when the top goes down either.
The other issue I had was the header, or the bar that the softtop is attached to that sits on top of the windshield frame. I'm not 100% sure on this one, but it seems that somewhere during the production years for the TJ, the header was redesigned. This redesign seems to have made it prone to warping from the heat. The one that came with my TJ was warped and wasn't sitting flush with the header seal. There should NOT be a gap between the header and the header seal. Even if you don't think air is leaking in, it probably is and the gap will cause turbulence and unnecessary wind noise. If it doesn't sit flush you either:
A. Have a warped header
B. Have a bad header seal
C. Both
I ended up having both. To solve the warped header, I bought a Bestop replacement, which ended up warping in a couple months. After reading that the older headers have a metal reinforcement bar instead of being just made of plastic, I bought a header from a 99 TJ and it fit a lot better than my Bestop replacement. There was still a gap so I ended up replacing the seal with a Fairchild replacement, which had extremely poor fit. I eventually ended up going with a mopar seal. This solved my gap issues. When putting up the softtop, I found it was easiest to attach the top at the windshield with everything still disconnected at the back, push down and forward on the header to close the gap, and then clamp down.
Seals
I found it necessary to replace almost all the weatherstripping in my 06 after replacing the header seal. Everything was either falling apart or very flat. I'm not sure about the half doors, but atleast on the full doors, there are two main seals. The actual seal that runs along the outside of the full door, and the glass run seal (seal that the window tucks into when you roll it up). For these two seals, the Fairchild options worked well for me. For the window glass run, it is Fairchild KD1012, and for the full doors it is KD3012. I have heard mixed things about the full door seals so buy with caution, but for me it worked just fine and seals well. Like I said though, had a bad experience with the header seal from them. I found the Fairchild ones on Rockauto a year ago or so but I don't see them anymore, I'm sure they can be found though if you look hard enough. Or better yet, go for the mopar seals if they are cheap enough.
Replacing the seals made a huge difference, I had no idea how much was leaking through them until I swapped them out, specifically the glass run seals because I haven't seen much talk about them on these forums. Less wind noise and whistling.
Sound deadening
Sound deadening the tub, doors, and A pillars helped considerably even with having a soft top. I want to make it clear here that I'm on stock sized tires that are all seasons, which are fairly quiet. I heard several people say that because of wind noise from the softtop being the most prominent, trying to reduce road noise wouldn't help at all. This was certainly not true in my case even having probably the quietest stock set up. I did two layers- 1. 80 mil Kilmat and 2. 157 mil closed cell foam
You do not need to cover the entire tub, door area, etc. with Kilmat. The purpose of layer one is to reduce the resonance frequency and dampen vibrations. You are essentially just adding mass to the large metal panels to make them less resonant. Doing this alone might not help much other than reduce rattles, but then the closed cell foam you add on top actually blocks the sound. You want to cover as much as you can with the closed cell foam. For the first layer of Kilmat/Dynamat, whatever you use, 60% coverage is okay. This whole process takes a ton of work and time. It's a pain. I found it easiest to just strip out the interior. Remove the carpet, remove the seats, pull the door card and scrub the bare metal until all the grime and rust is gone so the sound deadening can stick well. Again, I did the A pillars, the entire tub, wheel wells on the interior, and the doors. It also may help to treat the firewall but I didn't go that far because removing the dash sucks. Don't ignore the doors! Without sound deadening, they vibrate and amplify the sound in the cabin. Plus now they sound a lot less tinny and cheap when they close.
The Results
I am extremely happy with the results of all of this work. I have an aftermarket stereo I put together for my TJ and the road noise and wind noise are low enough to where I can actually enjoy it. I get compliments on it all the time because people don't expect a nice sounding stereo in an old TJ! I also tend to do a lot of interstate travel, and although the Jeep isn't what I'd call quiet, it is FAR quieter than it was when I first bought it. When I first bought my TJ it sounded like a tin can on the inside, very echoey and shrill, sort of like an old school bus. After all this work, it feels a lot more like an actual car. A lot of the mechanical noises, whines, etc is gone. The gearbox especially is a lot quieter. Some of you may not like that you keep it in mind
At this point, I think it is quieter than my old convertible MINI was. I can comfortably have a conversation with my passenger at 95+ mph. Of course when it's windy, it can still get a little loud but that's to be expected with any convertible. It feels a lot more relaxed and put together on the interstate now. 85-90 for hours on end is no big deal. I don't have issues talking to people in the backseat either. There's still a little gear whine and you can hear the engine when climbing hills but I think some of that is part of the charm of having an old Jeep. This has just helped a lot on longer 3000+ mile road trips when it comes to fatigue levels. Hope this helps someone!
The Top
The soft top that came with my Jeep was a SmittyBilt and it sucked. There was also missing hardware. First thing I did was replace the missing hardware and replaced the old top with a Bestop Twill Top. This upgrade got rid of the flapping sound at lower speeds, but it was STILL loud on the highway. I realized that majority of the sound from the soft top came from the constant up and down oscillations of the top cancelling out sounds in the cabin which made it difficult to hear my passengers and would drown out the sound system. That "boomy" low frequency sound from the top is what I'm referring to. Of course, this will always be present in any convertible, but I figured I can reduce the intensity though by reinforcing the top.
It worked, and this is my set up:
There are definitely ways to make it prettier but it's functional. I bought this mattress topper and then trimmed it so that when folded, it would line the area of the top from the sound bar to the header. The memory foam compresses and conforms to the shape of the top and braces it. To cover it up, I used this. To hold the mattress topper up and compress it, I used two PVC "top props". See this for more info. I did the same but used two! The foam mattress topper is just the right size, so I can shove it behind the backseat when the top is down. This probably made the biggest difference at high speeds or when it's windy out, and it's not very inconvenient to remove when the top goes down either.
The other issue I had was the header, or the bar that the softtop is attached to that sits on top of the windshield frame. I'm not 100% sure on this one, but it seems that somewhere during the production years for the TJ, the header was redesigned. This redesign seems to have made it prone to warping from the heat. The one that came with my TJ was warped and wasn't sitting flush with the header seal. There should NOT be a gap between the header and the header seal. Even if you don't think air is leaking in, it probably is and the gap will cause turbulence and unnecessary wind noise. If it doesn't sit flush you either:
A. Have a warped header
B. Have a bad header seal
C. Both
I ended up having both. To solve the warped header, I bought a Bestop replacement, which ended up warping in a couple months. After reading that the older headers have a metal reinforcement bar instead of being just made of plastic, I bought a header from a 99 TJ and it fit a lot better than my Bestop replacement. There was still a gap so I ended up replacing the seal with a Fairchild replacement, which had extremely poor fit. I eventually ended up going with a mopar seal. This solved my gap issues. When putting up the softtop, I found it was easiest to attach the top at the windshield with everything still disconnected at the back, push down and forward on the header to close the gap, and then clamp down.
Seals
I found it necessary to replace almost all the weatherstripping in my 06 after replacing the header seal. Everything was either falling apart or very flat. I'm not sure about the half doors, but atleast on the full doors, there are two main seals. The actual seal that runs along the outside of the full door, and the glass run seal (seal that the window tucks into when you roll it up). For these two seals, the Fairchild options worked well for me. For the window glass run, it is Fairchild KD1012, and for the full doors it is KD3012. I have heard mixed things about the full door seals so buy with caution, but for me it worked just fine and seals well. Like I said though, had a bad experience with the header seal from them. I found the Fairchild ones on Rockauto a year ago or so but I don't see them anymore, I'm sure they can be found though if you look hard enough. Or better yet, go for the mopar seals if they are cheap enough.
Replacing the seals made a huge difference, I had no idea how much was leaking through them until I swapped them out, specifically the glass run seals because I haven't seen much talk about them on these forums. Less wind noise and whistling.
Sound deadening
Sound deadening the tub, doors, and A pillars helped considerably even with having a soft top. I want to make it clear here that I'm on stock sized tires that are all seasons, which are fairly quiet. I heard several people say that because of wind noise from the softtop being the most prominent, trying to reduce road noise wouldn't help at all. This was certainly not true in my case even having probably the quietest stock set up. I did two layers- 1. 80 mil Kilmat and 2. 157 mil closed cell foam
You do not need to cover the entire tub, door area, etc. with Kilmat. The purpose of layer one is to reduce the resonance frequency and dampen vibrations. You are essentially just adding mass to the large metal panels to make them less resonant. Doing this alone might not help much other than reduce rattles, but then the closed cell foam you add on top actually blocks the sound. You want to cover as much as you can with the closed cell foam. For the first layer of Kilmat/Dynamat, whatever you use, 60% coverage is okay. This whole process takes a ton of work and time. It's a pain. I found it easiest to just strip out the interior. Remove the carpet, remove the seats, pull the door card and scrub the bare metal until all the grime and rust is gone so the sound deadening can stick well. Again, I did the A pillars, the entire tub, wheel wells on the interior, and the doors. It also may help to treat the firewall but I didn't go that far because removing the dash sucks. Don't ignore the doors! Without sound deadening, they vibrate and amplify the sound in the cabin. Plus now they sound a lot less tinny and cheap when they close.
The Results
I am extremely happy with the results of all of this work. I have an aftermarket stereo I put together for my TJ and the road noise and wind noise are low enough to where I can actually enjoy it. I get compliments on it all the time because people don't expect a nice sounding stereo in an old TJ! I also tend to do a lot of interstate travel, and although the Jeep isn't what I'd call quiet, it is FAR quieter than it was when I first bought it. When I first bought my TJ it sounded like a tin can on the inside, very echoey and shrill, sort of like an old school bus. After all this work, it feels a lot more like an actual car. A lot of the mechanical noises, whines, etc is gone. The gearbox especially is a lot quieter. Some of you may not like that you keep it in mind
At this point, I think it is quieter than my old convertible MINI was. I can comfortably have a conversation with my passenger at 95+ mph. Of course when it's windy, it can still get a little loud but that's to be expected with any convertible. It feels a lot more relaxed and put together on the interstate now. 85-90 for hours on end is no big deal. I don't have issues talking to people in the backseat either. There's still a little gear whine and you can hear the engine when climbing hills but I think some of that is part of the charm of having an old Jeep. This has just helped a lot on longer 3000+ mile road trips when it comes to fatigue levels. Hope this helps someone!
