Drone noise

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Has anyone installed a free flowing muffler on your first gen and ended up with a drone or rumbling noise. If so, did you figure out how to get rid of it, other then replacing the free flowing muffler with an factory one. It was only noticable when pulling a hill with a load at a certain rpm, but yesterday it was doing it at 75 on the freeway all the time. There is no exhaust leak, tailpipe sticks out past the fender. When under the truck, it is only at the tailpipe. When I walk around the truck, it seems to be everywhere and also in the cab. I am about to get rid it the muffler and go back stock.

Thanks
Rodney

 

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Rodney!

Which free flow muffler did you install? All have different sound characteristics & resonance pattern.

This is why I could not deal with the 'straight pipe' resonance characteristics with a free flowing exhaust. I had a straight pipe for 1 day before reinstalling the Big Banks muffler and eventually going to the Walker #21468. I love the sound of the Walker with no annoying resonance on my std. cab.

Keeno

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1992 W250 5spd. 3. 54 gears, LSD, JRE enhanced VE Injector Pump, BD High Output Injectors, Banks "Stinger Plus" consisting of a replaced 12cm2 wastegated housing, 3 1/2" JRE modified exhaust/muffler, pyro/boost gages, K&N, Skyjacker 2 1/2" front suspension lift to clear 305/70R/16 Goodyear MT's, Mag-Hytec, Amsoil, Rhino liner, Fully Chrominated Aluminum Aftermarket Accessory T-handle Shift Knob

 

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Before you junk the muffler you can try to move it to another position. I don't know what restraints you have under the truck, but moving the muffler forward may move the "drone" to an acceptable RPM range, like maybe 27 - 2800 Rpm. It may be worth it to try it out. The "drone" is a pulsation resonance in the exhaust pipe system.

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Jason's Lil' Mack - 89 D250LE 2WD 5 Spd 3. 54 Reg Cab. K&N,"tweaked pump", BD Injectors, Banks Pyro/Boost, 3. 5" Exst tail section straight. 23 Psi boost.
E&M Custom seats. Bosch H4, PIAA 80W/80W HdLites. 100W Drv,55W Fogs.
232,500 miles (372,000 Kms) 7700 Hrs.
The Original Turbo Diesel

 

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Rodney: You've probably checked the entire system for any interference and contact with the frame.
One last item: When the system is warm, loosen the first support clamp on the system, (the one at the downpipe, underside) and retighten the nuts. This relieves any hanger induced stress in the system.

 

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I don't know, but my dual 5" stacks right behind the cab make a heck of a "drone" noise! I love it! Who needs a radio?

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Mine: '93 250 LE 4x4 5spd 4:10 Pwr win/loc/mir,cruise,dual 5" chrome stacks,12cm2 turbo,pyro/boost,diamond plate tool box, CB, 16x10" AR rims, 285/75/16 Bf goodrich, US Gear E-Brake,Fuller Roadranger shifter, PW injectors, K&N. "wirenut_21529" on Yahoo Messenger
Moms:'96 Ford B-Series school bus (5. 9 Cummins!)I'm gonna Bomb it!
Dads:'94 GMC 2500 6. 5L Turbo

 

[Archive]

Thanks for the replies. I do not know which brand the muffler is, all I know is that the muffler shop said it was better then the Walker, but maybe that was a sells pitch, maybe he doesn't carry Walker. The problem yesterday is not a common thing, usually it is only on a hard pull at a certain rpm. I will look into doing as Old School says, dealing with the clamp and there wasn't any contact with the frame. I know if you put your ear near the muffler, while the truck is idling, it has like a low ringing noise, which I am sure it gets worse at a higher rpm.

Thanks
Rodney

 

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I like the stress-induced answer. My Buick makes the drone noise whenever it rains and the exhaust system gets soaked!

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http://coffeewithJesus. homestead.com/web1.html 89 1-ton, Amsoil System 3000 5-30,K&N air filter, cleaned-up exhaust, Dynomax straight-thru, rebuilt pump, 12cm wastegated turbo, thermostaticly controlled twin 14" electric fans, intercooler, modified 518 OD transmission, Gear vendors OD controler, R-134, louvered fenders, 93 aftermarket smoothe grille; 78 35'Avion, 93 Lance 900 slide in with generator and power jacks. Jesus saves!