Vibration after driveshaft loop install

[HwyCruiser]

I had a driveshaft loop installed last week by my dealer and now I have a new noise. It's sounds like a vibration while slowly accelerating from idle to about 2k. It sounds like something is loose in the exhaust. I had the same thing happen after the Magnaflow mufflers were installed and the Cobra exhaust x-pipe ass'y coupler flanges loosened up. They fixed it last time by replacing the flanges with a ball & socket type of coupler and all was good for a year.

Since the x-pipe ass'y had to be dropped during the driveshaft loop install I figured maybe the ball & socket coupler wasn't aligned / tightened back down properly so I had the exhaust shop look at it and they did a little tweaking and replaced the coupler bolts but the noise is still there.

The driveshaft loop bolts to the body without any insulating rubber pads, which I thought was odd. Could this be causing a low frequency vibration? Maybe the driveshaft wasn't indexed the same way on reinstall? I'm going to take it back to the dealer since I've eliminated what I thought was the obvious.

Any ideas would be appreciated.

[FordNut]

Maybe the driveshaft (not loop) wasn't indexed the same way on reinstall?
This gets my vote.

[TooManyFords]

Since the loop doesn't come into contact with any moving parts, why would it need to be indexed? I'm asking because I have one on order...
[in case I get mine running again!]

I know when I had my "loud pipes" attached to my cutouts, I could feel an exhaust vibration so I suspect that is the problem.

Keep us updated when you find out what it was and the fix.

John


PS: I will not be able to attend SSHS5. (sigh)

[Joe Walsh]

Driveshaft (not the loop) and pinion flange SHOULD have been marked for indexing PRIOR to removal of the driveshaft.
If it was re-installed 180 degrees off, then it is possible that this is the cause of the vibration.

[MM2004]

What ^^^^ he ^^^^ said.

The pinion flange and driveshaft should have a paint mark on both components that must align with one another for maximum balance efficiency.
The rear end and driveshaft are balanced as separate units, and should assemble together as described for a better reduction in NVH.

I would investigate this further as the loop would not affect balance as it is a stationary object.

Mike.

[HwyCruiser]

Yeah, that's what I meant to say. Driveshaft, not driveshaft loop on the indexing part. That's what I get for not reading what I type. :rolleyes: @ me.

[CRUZTAKER]

....Since the x-pipe ass'y had to be dropped during the driveshaft loop install ....
I didn't have to remove anything for the install. :confused:

[HwyCruiser]

What ^^^^ he ^^^^ said.

The pinion flange and driveshaft should have a paint mark on both components that must align with one another for maximum balance efficiency.
The rear end and driveshaft are balanced as separate units, and should assemble together as described for a better reduction in NVH.

I would investigate this further as the loop would not affect balance as it is a stationary object.

Mike.

So these paint marks are applied at the factory? I'll crawl underneath the car again to see what I can see.

The question about the loop was something the exhaust guy threw out since it provides a hard connection across the trans tunnel without any isolation causing a vib somewhere else. Everything seems to be tight though so it shouldn't be moving. I hate new noises right after something gets installed.

Thanks.

[HwyCruiser]

I didn't have to remove anything for the install. :confused:

The exhaust was obviously tweaked, one of the coupler bolts looked like it was stripped so the exhaust guy replaced them. Maybe because it looks so easy to drop? :dunno:

I just hope they didn't have the oil change guy do it. :shake:

[Tallboy]

Just out of curiousity, what brand driveshaft loop did you get, JD?

[HwyCruiser]

Just out of curiousity, what brand driveshaft loop did you get, JD?
Metco. It's a pretty stout piece and the alignment / spacing around the driveshaft is perfect. I got to take a good look at it when it was on the rack at the exhaust shop.



I know when I had my "loud pipes" attached to my cutouts, I could feel an exhaust vibration so I suspect that is the problem.

Keep us updated when you find out what it was and the fix.

John

Well, after taking a peek under the car I'm putting my money back on the exhaust. I talked to the guy about replacing a stripped coupler bolt while they were replacing the cats... "no problem chief, we'll fix 'er up"... and the stripped bolt is still there. WTF is wrong with people? :mad2:

I'm going to cut the bolt off and replace it this weekend and see if that doesn't fix it before I take it in again. I didn't see any paint markings but I didn't feel like putting the car on jack stands tonight.



PS: I will not be able to attend SSHS5. (sigh)

:depress:

[AzMarauder]

Maybe the driveshaft wasn't indexed the same way on reinstall?
I'm going to vote this way as well !

That is what I would check....

[snowbird]

I had a driveshaft loop installed last week by my dealer and now I have a new noise. ....

Any ideas would be appreciated.JD,

Every time i went for a gear install, i always insisted that they mark the driveshaft end so that they reinstall it at the same place (for balance) even if some installer pretended that it was a urbain story. I,m not shure if it was necessary (insisted and won) but it never vibrated after install. Maybe a very close look at it could help you figure out where it was to try it back.

Also, i had some kind of the same trouble and rpm range a couple months back and went at a muffler shop and it was a bad cat that we immediatly replaced. I'm guessing your muffler guy already discarted that possibility.

Lately, i bought a set of used stock mint condition 2004 Cobra stainless mufflers on EBAy (what a deal at 20$ excluding shipping) that i wanted to try some time in the future. A month ago, another vibration at idle or low rpm. Back to the muffler shop and this time, it was the internals of one muffler that unsoldered itself. Here was my excuse to ditch the Walkers since i had the Cobras in the trunk.

Also on another recent tread, it s been said that Martyo had some kind of a low vibration problem Marty's Doctor Appointment Today: (http://www.mercurymarauder.net/forums/showthread.php?t=21975) .... but i'm not shure if its related to your problem !!
Now, you have 3 more possibilities !!!:banana:

Hope it help. :)

[AzMarauder]

JD,

Every time i went for a gear install, i always insisted that they mark the driveshaft end so that they reinstall it at the same place (for balance) even if some installer pretended that it was a urbain story. I,m not shure if it was necessary (insisted and won) but it never vibrated after install. Maybe a very close look at it could help you figure out where it was to try it back.

Also, i had some kind of the same trouble and rpm range a couple months back and went at a muffler shop and it was a bad cat that we immediatly replaced. I'm guessing your muffler guy already discarted that possibility.

Lately, i bought a set of used stock mint condition 2004 Cobra stainless mufflers on EBAy (what a deal at 20$ excluding shipping) that i wanted to try some time in the future. A month ago, another vibration at idle or low rpm. Back to the muffler shop and this time, it was the internals of one muffler that unsoldered itself. Here was my excuse to ditch the Walkers since i had the Cobras in the trunk.

Also on another recent tread, it s been said that Martyo had some kind of a low vibration problem Marty's Doctor Appointment Today: (http://www.mercurymarauder.net/forums/showthread.php?t=21975) .... but i'm not shure if its related to your problem !!
Now, you have 3 more possibilities !!!:banana:

Hope it help. :)

Don't ask someone to mark your Driveshaft... get some paint and do it... :)

Are the Cobra mufflers better flow wise than our stock mufflers? (OEM are Walkers?)

Are the exit and entrance for the Cobras the same as the MM?

Did it change the sound? ( I have Cobra Mufflers coming out my ears) (at least two and maybe 4)

[snowbird]

Are the Cobra mufflers better flow wise than our stock mufflers? (OEM are Walkers?)

Are the exit and entrance for the Cobras the same as the MM?

Did it change the sound? ( I have Cobra Mufflers coming out my ears) (at least two and maybe 4)Will answer via PM so we do not highjack JD tread:)

[MM2004]

No. The paint marks are applied by the supplier before shipping to the OEM.

One paint dot will be on the tube of the driveshaft (axle end) close to the circle weld and another paint dot on or near the pilot flange of the rear end.

There are times that the paint dots will not line up exactly, but should be within very close proximity to one-another.

Typically, the paint dots are yellow in color. (See the image below taken in our shop immediately following final balance).

Another thing to look for is a flush fit of the driveshaft flange to the pinion flange. The tolerances of the pilot on the driveshaft flange is ~.0005, nearing a perfect fit prior to torqueing the bolts down.

Mike.


So these paint marks are applied at the factory? I'll crawl underneath the car again to see what I can see.

The question about the loop was something the exhaust guy threw out since it provides a hard connection across the trans tunnel without any isolation causing a vib somewhere else. Everything seems to be tight though so it shouldn't be moving. I hate new noises right after something gets installed.

Thanks.

[HwyCruiser]

Just to follow-up, TMF wins the prize.

It turned out to be the driver's side ball & socket flange on the x-pipe ass'y wasn't tight enough. The old flange bolts, being stripped and bottomed out, were just loose enough to let the exhaust pipes flex at the connection point. I wound up taking it back to the exhaust shop today because I didn't have any time for it this weekend and the muffler wrench had to cut the nuts off with with a torch and heat up and beat the bolts out with a hammer. Good thing I didn't get the chance to mess it up any worse.

[DEFYANT]

I love threads like this. The Problem. The Speculation. The Brainstorming. and The Solution. All in 17 posts.

Glad it worked out well JD!