Vibration at 1500-2000 RPM

[TrickyP]

Ok, so here's my situation. I've got a 2006 Mustang GT with 43,000 miles and a manual transmission. I can't quite remember when it started, but I've had a dull vibration from 1500-2000 RPM. Dull vibration = barely noticable unless you are "looking for it". It was most noticable on the highway from 55-60mph. Once I got out of that rev/speed range, the vibration went away. For awhile it was bearable, but still noticable. That was with the stock motor mounts. I recently put prothane motor mounts in and the vibration is still there, but of course, now more noticable. I've checked the following items and ruled them out:
1. Motor mounts installed properly and torqued to spec
2. Driveshaft is at the proper angle (1-pc, but I'm at stock ride height)
3. Suspension components are tightened to spec and in proper alignment

If I rev the engine in neutral, I get the vibration. When the car is in gear, I get the vibration in all gears from 1500-2000 rpm.

I'm looking for help, ideas, thoughts on diagnosing the problem. One thing I will check tonight is to see, if for some reason, my transmission mount is loose (I don't know why it would be since I never touched it). I'm also going to check the transmission mount per TSB 08-23-4 (although the problem described in that TSB doesn't describe my problem). I'm not focusing on the transmission in particular, I'm just at a loss for what the problem could be.

Ideas?

 

[Bill220]

Mine made a similar noise/vibration around 60-65 whether on decel or accel. Rear end needed a rebuild at 15,000 miles.

Flip your back seat down and see if you can hear it better.

 

[TrickyP]

Mine made a similar noise/vibration around 60-65 whether on decel or accel. Rear end needed a rebuild at 15,000 miles.

Flip your back seat down and see if you can hear it better.

Not sure if it makes a difference, but I checked during lunch...I get the vibration while sitting in neutral as well. That makes me think it is something with the engine?

 

[RLF9409]

Any recent mods?
I had a vibration with my new 1 piece DS. I rotated it 90 degrees and it went away.

 

[SuperchargedStang]

I was gonna say motor mounts, but you said you all ready did them.

 

[TrickyP]

Checked the transmission mount according to the TSB...nothing wrong there.

I don't think it is the driveshaft since I get vibrations while sitting in neutral and parked.

I'll check the motor mounts again, but I think I had this problem before the motor mounts. If the 2 bolts to hold the mount are tight and the bolt that holds the mount bracket to the mount is tight, what else could it be?

 

[RLF9409]

New clutch?

 

[TrickyP]

Clutch is still stock w/ 43,000 miles on the clock.

Recent mods: motor mounts, 1-pc driveshaft, panhard bar. I really think these mods may just be amplifying an already existing problem. This isn't the first time I've done a 1-pc DS or motor mounts, so I'm kind of lost at the moment.

 

[BruceH]

Does it do it with the clutch pushed in too? Have you checked the harmonic balancer? The stock unit is two piece and sometimes the bond separates. Some UDP are known for this too.

 

[skwerl]

^ Like Bruce said, I'd check the harmonic balancer. Another possibility is the flywheel wearing funny but the stock flywheels are pretty good.

 

[TrickyP]

Not to sound like a retard, but what exactly am I looking for with the harmonic balancer?

 

[skwerl]

Look for any displacement of the rubber strip between the inner and outer shells. If there's any evidence at all that it has shifted or hemorrhaged then replace it.

 

[BruceH]

Not to sound like a retard, but what exactly am I looking for with the harmonic balancer?

Grab the outer ring and see if it moves. If something is wrong you will notice it.

It could also be something in the glove box or door panel that's rattling. My sos pods will do it sometimes.

 

[TrickyP]

Here are a few pictures that I just took.

Skwerl--I circled the area that may be an issue. It looks like it is slightly bulging out, but not a whole lot....this would be my first time looking for something like this, so I'm definitely looking for opinions.

 

[skwerl]

You can pick up a new one for $100 plus about $8 for the bolt (one use, TTY). I may be wrong but I'd replace that just to be sure.

 

[TrickyP]

You can pick up a new one for $100 plus about $8 for the bolt (one use, TTY). I may be wrong but I'd replace that just to be sure.

Sent you a PM.

 

[TrickyP]

If it ends up being the harmonic balancer, what causes the stock one to go?

 

[RLF9409]

I would recommend unbolting and rebolting the engine mounts. Even if the HB is causing a vibration I would think the motor mounts would absorb it but then again the vibration might be too bad for it to be absorbed.
Does the engine shake? Heck I have BBR stage 2 cams with a heavy lope and no vibrations in the cab, other than at idle...
Could it be an exhaust drone?

 

[TrickyP]

I would recommend unbolting and rebolting the engine mounts. Even if the HB is causing a vibration I would think the motor mounts would absorb it but then again the vibration might be too bad for it to be absorbed.
Does the engine shake? Heck I have BBR stage 2 cams with a heavy lope and no vibrations in the cab, other than at idle...
Could it be an exhaust drone?

Yeah I'll look at the mounts this weekend when I can get under the car and full inspect everything. I'll double check the mounts and see that everything is tight.

I know a few people mentioned loose exhaust or parts in my car...definitely not the case. This is a vibration that makes the whole car shake from 1500-2000 rpm. I had my wife keep the car in that rev range while I was parked and I could feel the engine shaking when I placed my hand on it, but it wasn't bad enough where I could see the engine shaking.

I'm probably going to order a harmonic balancer, but I'm also looking for other ideas/suggestions as well. I know the pictures a somewhat crappy, but if anyone can tell me if that harmonic balancer on my car is gone or not, I would greatly appreciate it.

 

[RLF9409]

I don't see anything visually wrong with your HB.
When the car is running do you see any movement with the HB?