I STILL have a drivetrain vibe and HOW do I get it fixed?

They are loud. I am running a pair of Flowmaster super 44s dumping at the axle.

I have had a couple people say exhaust, and if I can prove it to myself, I will relax and forget about it.

I am seriously thinking about buying a couple pieces of that flexible tubing and just rigging it to extend out past the rear bumper, and driving it a few minutes. If the vibrations go away, I will rest assured that it is NOT drivetrain related and live with it. Or maybe someday add tailpipes, if it continues to worry me.

 

It was my right rear wheel. I kissed a curb in the snow once. Does the header touch your gear box? That was one of my problems.

 

Don't they use sound waves to bust up kidney stones? If sound can do that...it can rattle a dash

 

All noises are vibrations or more correctly an oscillating vibration.
The best way to see that in your head as an example is plucking a guitar string. Also one vibration my excite another. Again think of a guitar hit the Top E string hard and you will hear the other strings ever so lightly if they are not muted by your palm. You need to find the source. As a mechanic I have a really nice stick on microphone set. I can stick 4 microphones on and drive a car and listen until I zero in on the vibration. Pretty cool

 

so scooper, has this vibration been there with all your different comibinations that you have had?
i know that you have had different motor combos, different muffler combos, and other stuff.
i dont like the idea of using the caltacs to adjust your pinion angle. thats a preload on to the spings and can cause the pinion angle to not be able to move or move in a different way than is normal. you may want to try puting a 1/4" spacer in the trans mount to see if that has and effect. speaking of effect what changes have you done that has has and effect on the vibration. i have see drive shaft tubes that are not perfectly round and can be balanced but will vibrate when driving a car.
your rpm situation does sugest that its engine or exhast related vs drive line related. do you have turndowns on the end of the mufflers?
ive heard that if you point the turndowns so they are angled down and towards the center of the car the coliding exhast pulses help cancel each other out.
do you have and x or h pipe?
ive see where they will make a car louder or make it quieter. they are susposed to be located where the exhast starts to stall out in the pipes after leaving the headers. this point creates a hot spot that can be determined by puting paint or even wax on the pipes then going for a good full throttle run then seeing where its burnt off or bubbled up. if you put the h or x pipe at that point it does lower the noise and vibration.

 

Bring it up here to me Scott. I'll LOOK at it for free

 

have you had the tires and wheels balanced? my truck has a similar vibration but i have switched everything but the wheels.the new exhaust i just had put on rattles the hell out of the truck between 2000-2400 rpm,all they changed was a rusted 40 series flowmaster to a super 44 series flowmaster.

at cruise speed put the trans in second but keep your speed up,if the vibes are less or gone then the problem in engine,trans or exhaust not drivetrain.if they stay the same or get worse.hows the front alignment?tread on any of the tires worn funny

 

An out of balance or bent wheel creates a completely different frequency from a driveline vibe. One cannot be mistaken for the other by an experienced driver. I've got 18" Turbo Tubes on mine with 8" angle cut straights ending on either side of the rear chunk. They're pretty loud at highway speeds, but the sound is completely different from Flowmasters. Try quieter mufflers or as you suggested, extending the tailpipes out the rear before going farther.

 

If I remember right from his previous thread it didnt do it with his old exhaust. I think he had dumps in front of the wheels or sidepipes, cant quite remember. I think he recorded it in the last thread and I commented on how my daughter said that sounds just like your exhaust vibration Dad. She knew that because I explained the noise to her a few times on drives. She learns more than I realize. I hope it was his car and I'm not mixing up threads. My first Mav did it with dumps and this one does it as well. I can rattle a set of keys right across the shelf at 3000rpm. It starts around 55 mph and goes away at 70mph. Put tail pipes on my first mav to shut it up and plan on the same for this one in the Spring. Mine is 100% not a drivetrain vibration. I wouldnt even waste my time looking for it cause it aint there. Heard and felt lots of drivetrain vibes and balance issues over the years and this noise certainly isnt one. Just good old exhaust resonance that can make you nuts at the right speed.
That is my car though. His may be worse than mine???

 

the fact that it doesnt to the vibration at the higher rpms really says that the problem is not in the driveline. soo that leaves the motor or exhast. sence exhast is the easyer thing to change i would try doing that. i understand that scooper is at his wits end and just wants to take it to a shop, but as darren said its going to be very hard to find somebody who will be willing to put the time into it. so scoop you need to decide what you want to try. if you dont have a h pipe i would do that first. find the point of resonance like i described earlyer and have an h pipe put in right there by an exhast shop. that would be the first thing i would do. its susposed to free up some power wich is a plus and should have an effect on the exhast sound.

 

It started doing it with the dual exhaust and glasspaks exiting before the wheels. But it was a quiet drone, sounded like an old prop-driven bomber plane.

Then when I added the flows downturned at the axle, it got worse, so I am leaning toward the exhaust fix first.

I initially thought I had a poorly balanced engine, but when I get on it up over 5k rpms, it just purrs and drives smooth.

But I spend most of my time around 3000-3500 and it is killing me there.

 

Scott; I see you have a 5.0. How is the engine balanced? Do you have a 50oz flywheel and balancer? You need them matched to keep the vibes out. Also, check the flywheel. I had a Fidanza 50oz flywheel (removable weight) that was bad from the factory. I had the proper weight on it, but it still didn't balance right. Shook me out of the car. I replaced the flywheel with a stocker (50oz), and it is smooth and quiet. If you have an automatic, it still applies...need a 50oz flex plate and balancer. Also, check you balancer to see if the inner polymer ring is bad, or has let go. It will move the timing around and cause all kinds of problems. Hope this helps. Good luck, and keep us posted on the progress. Later,

 

I know this thread has gotten long, but somewhere early on I mentioned that I have a new SFI 50 oz flywheel (flexplate) and new Professional Products 50 oz balancer.

i am sure it isn't engine vibes. I can put it in neutral and rev it all day with no vibe. It is either drivetrain, or more likely, from the responses on this thread, exhaust vibes.

 

I should have done a recording of my car on the HWY before I put it away. I think you would be surprized at the similarity to your noise/vibration. I mean come on Man my daughter knows its exhaust drone. Maybe you should bring it up here for her to diagnose??

Sorry that was uncalled for. And no wise cracks about my daughter please she's only 12.

Seriously, I think Bryant is on board with me on this one and his idea of the h-pipe may help without tail pipes. I do like the sound of mine with the turn downs from the outside as opposed to tail pipes. Was planning on an h pipe anyhow so maybe its worth a try before tail pipes. We have this terrible thing called Winter up here though so I guess you'll be the guinea pig.

 

Scott...My Sprint has that same vibe/drone at speed...Between 3K and 3500.It has full length headers and 2 1/2" pipe to a pair of 44s' and tail pipes(no H/X pipe or cross over)My blue mav did the same with cherry bombs 2 1/2" pipe on stock exhaust manifolds and dumps behind the rear tires.As soon as I put in a crossover pipe(H pipe) it stopped...Might be the thing to do to save your sanity...Good luck!!!