[jaja6009]

My first problem has surfaced on my car.
05 GT 5sp
Saleen blower
CHE LCAs

Today I was cruising on the expressway and was doing 80-85mph. I was in 5th and noticed a lite whir whir sound and then when I would accelerate the shifter would shake. Im guessing driveline harmonics. i have the stock driveshaft in. I could not get it to recreate at any other speed in any other gear. I am thinking that since Ive never cruised at 85mph before that the problem has always been there. Any time I have been at 80-85 I have been accelerating and in 4th and I guess me accelerating I did not notice it. But then again it may be new. Any help would be appreciated. Next time I get my oil change Im gonna have the dealer look at it and see if they can find anything. The only other time I had vibration/harmonics was when the car sat for weeks and I drove it it had some steering wheel shake. But that went away after a day and never came back and that was a year ago.

[Wes@PHRP]

You should not have a vib. at the speed but it does happen and can happen for many diff. reasons... Its best to get it looked at asap just to be safe. That said you may want to put a single piece shaft instead and not worry anymore! Sometimes the rubber bushing. Good Luck!

[Back@itagain]

My 1pc made symptoms at these speeds much worse. If it is harmonics, you can notice it through the stock D/S but usually at higher speeds. All that rubber does do a good job of dampening. There are plenty of benifits to swapping to a 1 p/c but curing a harmonics issue is not usually one of them...

[stlwagon]

I don't think a little shaking of the shifter is much to worry about.

[Wes@PHRP]

I have several S197 mustangs and none of them have a vibration... Once I removed a 2 pc. shaft from one of our GT500's and put in a 1 pc... then went back I had a vibration at 105mph in 6th. checked it out and put the 1 pc back and no prob. Now pinion was also correct on the 1 pc. Your pinion angle should be dead on from the factory. As long as you havnt changed your upper control arm (3rd link) shouldnt be off. I also had to replace several clutches on the Gt500's as well with the current recall and thats when I found out about the center carrier bushing, could be off. That came back from Ford that way after a trans and clutch replacement.

[jaja6009]

I still have the stock upper control arm. I have CHE lower control arms but they are not adjustable. I had my clutch replaced so the tranny as been dropped. Do you think my center carrier bushing could be off? I have to go find and read about that above recall. Next time Im at the dealer I will have them take a look. As I said I never noticed this before but then again I have not often cruised at 85mph in 5th. I hate problems. Makes me want to revive my plan of getting a GT500 and just swapping in a whipple kinda like your project. I am about to buy a 1pc driveshaft and adjustable upper control arm but now I ave to look into this problem. Im gonna go out on the highway soon and gather as much info on the problem as I can. Hope I dont get any tickets. Im pretty sure it does not do it in 4th. But in 4th the engine is screaming and its harder to hear if the "whir whir whir" sound is there.

[jaja6009]

I found the problem and I am an idiot. The first thing I did after noticing the vibration was to make sure the wheel balancing weights had not fallen off. It was dark when I looked and I though I saw that all four wheels were OK. I went and checked again in the daytime the other day and the passenger side rear wheel was missing its weight. I guess I saw the spot on the wheel were the weight was and thought it was the weight. I have not tested it back on the highway as when I tried to get up to 80 a State Trooper was nearby. But Im almost certain that was the problem. Moral of the story dont be lazy like me.

[jaja6009]

Please help!!
The problem is not gone. I finally got out on the expressway and the problem is still there. I tested it today and here is what I found. 80 mph and up in 5th gear there is a whir whir sound. (Cant tell exactly where it is from). At 80mph if I hit the gas there is a shaking/vibration and loud rattling sound coming from the shifter area probably forward of the shifter. At 80mph it is around 2500rpm. The problem never happens in other gears at that rpm. Every other gear is good. The only thing I have not tried is 80mph in 4th gear. Once again I saw State Troopers and had to end my testing. Any ideas will be appreciated. Im taking the car to the dealer on Monday but would like opinions.
The only driveline and suspension things changed are a Roush P51 clutch disk with stock pressure plate and stock flywheel. A new stock flywheel was put in with the clutch. And for the suspension I have nonadjustable CHE rear control arms.
Are clutch disks balanced? I hope its not the clutch disk. Other than the above problem there is no vibration at any other speed. I had the one wheel with the missing weight rebalanced. Could other wheels be out of balance since they are the original rubber from 2005? I dont know how to check pinion angle but I will tell the dealer to do so. Teh sound almost seemed like the shifter handle was rattling. I checked and the bolts were tight. I also tightened the shifter bolts under the car.

[sqidd]

First it should be defined as what it is. It is not a driveline “vibration” problem but a driveline harmonics issue.

There is no way of guaranteeing that you will not have harmonics issues. Contributing factors to driveline vibrations are:

• Driveline angles
• Driveshaft balance
• Harmonics from the rear end which includes a change to the gear, diff, axles, bracing, cover, etc can all contribute to driveline harmonics.
• The wheels and tires you are running can contribute to driveline harmonics.
• The upper and lower control arms you are using can contribute to driveline harmonics.
• The springs and shocks can affect it too.
• Going with an aluminum shaft opposed to a steel shaft will affect harmonics even if they are the exact same design.

Pretty much anything can cause a driveline harmonics problems depending on the specific combination of parts. That’s why some people have no driveline harmonics issues and some do. There does seem to be a trend of the more aftermarket parts you have in your driveline the more likely you are to experience driveline harmonics issues though. That being said there are stone stock cars out there with harmonics problems.

Next will come a ton of posts from people telling you if they do or do not have driveline harmonics issues and what driveshaft they are running. Unless you are planning on driving their car that information is useless to you. Unfortunately going with a 1pc aluminum driveshaft is a crap shoot.

[sqidd]

In addition to the above:

The bottom line is that you can have perfectly balanced/round wheels and tires, perfectly set up rear end, perfect driveline angles, clutch centered perfectly, everything torqued to spec, etc and still have a driveline harmonics issue. In most cases you will not find that any one component is “out” and causing the harmonics issue. As stated above if all of the components that can affect driveline harmonics spec out perfectly on their own that does not guarantee you that when they are combined as a system you won’t have any harmonics issues.

I dug all my notes up that I took while mapping out the driveline angles in the chassis the other day and compiled them into something cohesive. The bottom line is Ford stuffed a huge motor with a very high crank centerline and a Trans with a relatively low output flange centerline into the front end of a car that they wanted a certain look from. Sacrifices were made. I know exactly how to solve the driveline angle issues in the car. On a basic level it’s easy. The problem is easy. The Trans output flange as delivered points at a point that is lower than the center of the pinion flange centerline even with the car not being lowered. It gets worse when the car is lowered. In a perfect world the Trans would point at a spot above the center of pinion flange. If it were set up like that you could get the driveshaft set up to be perfectly in phase (something like a DS angle of 1.5deg down coming off the trans and 1.5deg up coming off of the pinion). As delivered that can not be done because of where the Trans points.

It could be solved by shimming the Trans at the cross member till it pointed up a few more deg but there is not enough room between the Trans and the tunnel. Not even close. You can slam the Trans into the tunnel and you will only get .4deg out of it. You would have to move the tunnel to make it better. Obviously a lot of work.

Another way to solve it would be to lower the motor but even with the pan sitting on the steering rack I could only get .6deg out of it which was not enough. And obviously you can’t have the pan touching the rack anyway. And you can’t move the rack “down” because that would make the current bump steer issues even worse to borderline in-correctable. To compound the problem the back of the pan was quite a bit lower than the K-Frame which is just begging to get broken open. To get the motor low enough to even be in the ballpark you would need to dry sump it. Of course that would pay you back with a ton of performance advantages (lower C of G, more HP because of less windage, more HP because of the small vacuum placed on motor, oil stored in trunk which moves the weight to were you need it most, you could run a 10qt system if you wanted to and never have any oil issues, etc). Of course the downside is that it would be very custom, incredibly expensive, incredibly complex and nudge the car pretty far toward “race car”. I think at some point I will dry sump my car but that would be at least 2 more years and the car will be pretty far down the development phase by then and to a point where most people don’t want to take their cars.

If you combine shimming the Trans and lowering the motor as much as possible it’s still not even close to where you want it.

The last Idea I have to fix the situation, and one that would not be very expensive if done in a large enough quantity would be to remove the trans tail/flange and bolt on a custom mini “transfer case” that would simply raise the trans output flange up and therefore relocate the output flange higher. There is room in the tunnel for that because you wouldn’t be moving the large part of the Trans. And while designing it you could ditch the output flange in favor of a “normal” slip yoke so the driveshaft would not need to telescope like they do now which does not help the DS balance/whip/harmonics one little bit. I could make this part out of billet without much trouble and use some OEM 1:1 “transfer” gears of some sort so durability was already proven. The problem is making one would cost at least $3,000. If I could put them in production and make 1000 units I could probably do it for $500. I highly doubt I will find 1000 people ready to sign up for one though. It would be far less expensive for me to dry sump my motor and lower it in the chassis a ton.

So there ya go. It’s fixable to the point of having zero issues no matter what combination of parts you are running by setting the car up so you could obtain an ideal driveline layout but not one of them is very easy or cheap.

Ramble over.

[Back@itagain]

Originally Posted by sqidd

Ramble over.

Thank God!!!!

Can you finish making one part before you start dreaming up the next? You know you have guys already salivating about a manifold to fit the GT500 blowers to teh 3 valves.

[cman]

That's an awesome explanation Sqidd. I would like to mention one thing I noticed with the vibe in my 05. I noticed when I installed aftermarket LCA, the harmonic vibe did not change much. However when I installed an adjustable aftermarket UCA set to the same length as the stocker, the harmonics were much better. Perhaps it has a something to do with the bushings being stiffer than the soft stock bushings and controlling the axle movement better

[sqidd]

Originally Posted by Back@itagain

Thank God!!!!

Can you finish making one part before you start dreaming up the next? You know you have guys already salivating about a manifold to fit the GT500 blowers to teh 3 valves.

That's what I do at 4am and can't sleep

I also figured out the flow rates for all the popular twin blade TB's last night too

[jaja6009]

Thanks for all posts helping me out. Actually Sqidd I was hoping you would respond as you know your stuff. I have a dealer appointment on Monday. I did notice something else today when moving the car out of the driveway. There is a creaking moaning sound coming from the front end when braking. I have been busy lately and have not had much time to get under and look at the front suspension. I guess the dealer will have to check. Im hoping that whatever is making the sound up front is causing the harmonics problem. I just hope the dealer figures it out and its covered under warranty. Thanks again.

[SoCalSam]

Before you take it to the dealer, call the shop below and maybe these guys can help:

Web site: Home
DriveLineService@hotmail.com

Drive Line Service of NJ, Inc.
622 Rt. 46W Clifton, NJ 07013
Phone (973)473-7900
Fax (973)253-7132