Driving my 01 L back from Georgia last night I noticed a wo-wo-wo resonating sound coming from under the truck only after 90 mph .Anyone know what this is.Under carriage is dry and all bolts on driveshaft are tight.possibly the exhaust equilization issue? Any ideas would be helpful.

 

Exhaust all the way. See:

https://www.f150online.com/f150board...ML/011006.html

The wo-wo-wo is the giveaway. Not a difficult fix, you just need somebody to believe you.
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2001 Red Lightning Delivered 3-15-2001, 2" Aim Lowering Shackles, Hitch Removed, Group Purchase Floor Mats, Modified Light Switch for Fogs, JDM Filter Kit, Single-Bladed T/B, Keyless Entry, 22% Tint, Other Goodies. Best Time: 13.41 @ 104.37 mph

2000 Red Lightning - #835 of 4966 Sold 3-8-2001

My Zing.com Album Click Here



[This message has been edited by WHAT04 (edited 04-23-2001).]

 

What04 your right on LOL hey thats my post.
Did you get your Magnaflow put on yet, and how do you like it?

Mondo1 I had the same thing, I bet if you take it up to 95 and then quickly let off the gass you will really hear it then too.

I love the Magnaflow muffler nice and smooth with a nice growl when you get on it, and it got rid of the wo-wo-wo sound.

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SILVER 2001 LIGHTNING
Built 02/14/01
Picked up 03/03/01
Sportmasters tonneau
Bedrug
Alpine head unit and six disk changer.
JL Audio speakers
Magnaflow muffler
JDM BigMouth Filter.
http://donf150.tripod.com/Welcome/id6.html

http://www.zing.com/album/?id=4294607313

 

Got the same sound, I can actually "feel" the resonance on a nice smooth piece of interstate highway. I guess this gives me a reason to order a muffler now huh?

 

I installed a Magnafow ,the smaller louder one. Still have the resonance. I feel it as well. Wonder if the weights work on aftermarket mufflers.

 

I went with straight pipes, got no vibes, of course the wipers don't work so good when you're goin' 120 or more!!!!!

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01L,Lowered, Black,Downey SST,Straight Pipes,Chipped........ Toy: 91 Heritage Softtail Classic/Lowered

 

I ran straight pipes on My 99's. I loved the sound. I would just crank the tunes up on longer trips. Never bothered me. Bothered the wife. So she never rode with me much.
Her loss. I compromised see "pussed out".
Well now I may hack it off....The muffler. I know what you're thinkin`....

 

Hey Twisted,

Don C. has weights on his Magnaflow. Seems to work. There's more to this than just an aftermarket muffler. Need to "neutralize" the system and use counterweights.

Don C - I ordered the muffler on Friday and am expecting it any day. Hopefully I can find a competent install shop. Will keep you posted. Interestingly, I was driving today with the slider open only - had 22% tint installed today - and you can sort of hear and feel the exhaust pulses setting up the underfoot vibration. Hard to tell and it's very touchy with regard to weather and engine load, but something is there.

Hope the muffler cures it.

 

What04,does Ford know how to "neutralize" the exhaust, or will they look at me like I'm nuts? I think I would like this done.Thanks to all.

 

Mondo1: There's a good chance that you'll get the "deer in the headlights" stare back at you, just like I got from this board when I suggested that was what was being done.

Anyway, all that is being done is relieving the strain in the exhaust from trying to match the parts up during assembly. What they did with mine was to loosen all the joints in the entire exhaust system except for the exhaust manifold bolts on the engine. Then fire up the engine and let the exhaust get good and hot. Then the transmission is shifted from Park into Drive and reverse a few times. This will allow the engine and transmission to rock on their mounts and shift the exhaust system joints to where they want to be. Now tighten all the joints again.

Apparently, the '01 have a new brace in the exhaust that attaches to the transmission. My tech. removed this piece. Also the counterweights were added. The exhaust dampner counterweight part number is: XL3Z-5G209-BA Two are required. These just replace the clamps on the front of the muffler.

Each of these steps were performed with a check between each to see what happened. The vibration was reduced each step of the way. You can check it out by putting the tranny in Park and slowly revving it to 3000 rpm and beyond. Right now you probably will get the wung-wung-wung sound in the cab by doing this.

Also see this post:

https://www.f150online.com/f150board...ML/010008.html

Hope this helps!!

 

Thanks What04. That was the complete answer I was looking for.Very thorough! Thats what websights like this one should be like.By combining all of our experiences without the B.S.Thanks again!