Vibration between 50 & 70 mph

FYI
At 800 miles on my car I got a nail/flat and had to replace the rear tire. Since then I have had the vibration.
I had them redo the balance several times but no luck getting it out.

 

Sorry to hear that! A tire vibration, however, is nothing like the drivetrain vibration we are discussing. A tire is a shake/bounce. The drivetrain vibe is a hum/roar that is similar to the sound a turboprop airplane makes when flying.

 

I wonder what is the difference between the jr3z-4a263-b used on the 18,s
the the https://parts.levittownfordparts.com/oem-parts/ford-damper-fr3z4a263a
used on 15-17

 

Yep, those are two different part numbers. The FR3Z is for the 15-17 models - but it would be interesting to see if the JR3Z works better on the 15-17 models. Did the subframe damper even come on all 15-17s? The talk in this post makes it sound like there was no damper piece on @CNCLester's 2017 S550 that he was comparing to his 2018.

https://www.mustang6g.com/forums/threads/vibration-between-50-70-mph.15990/page-173#post-2261173

Update - I just looked under my 2015 GT and it does not have any damper bolted to the subframe. Looks like the big metal damper piece would nest into the inside of the differential's big rubber insert used on the big subframe bolt.

So when did Ford start adding this piece to the 2015-2017 model years?

 

My 17 GT doesn't have the damper either, of course, that's why I ordered one to give it a try.

 

Wonder if it's an added part to the 15-17 models as only part of Ford's driveline vibration fix, and all 15-17 models never came with it off the assembly line?

 

No.

When my prior 2016 was being worked on (over, and over and over), no such part was discussed or event attempted to be part of the Ford Engineering “fix” - never was attempted nor was it ever part of any of the (2) existing SSM’s discussed earlier on in this thread, or on any of my numerous Ford work orders that had extensive notes).

My prior 16 had very LENGTHY repair procedures and attempts at fixing the driveline vibe -to the point that the Dealership was in constant contact with Ford Engineering Team as well as (3) FSM’s came to the Dealership with special equipment, to test drive and to guide the Tech along with all of the attempts at repair.

For the 2018’s, especially the automatics, remember the 6R80 has been replaced by the 10R80 and associated parts are most likely different on the 2018 pertaining to the driveline.

There was also discussion early on in this thread (and a thread in the trans or suspension sub forum) where some folks had stated that the 2015-2016 EB w/PP had a similar “weight” affixed to the rear subframe assembly. If I recall, I think [email protected] also confirmed that such a part was on the rear subframe for the EB only. Now, I do not know if THAT part is one and the same as the weighted part now being discussed.

 

Today i cleaned the car and decided to removed the butt ugly wheel locks which were huge and stuck out like a sore thumb and low and behold my vibration has all but disappeared. Some times the vibe was worse than other times, which i assume is based on where the lugs were in time with each other or not. I was surprised this made such a difference given 35 yrs in the automotive trade and i was convinced it was driveline vibration though not as bad as some described with having the rear view mirror vibrating. FWIW i drove about 2 hours after changing the nutz and it was not on my mind at the time, it was a holy shit thing when i was on the hwy and i says to myself, self the car she not viberating. I had also contacted DSS and they mentioned that the Mod motors have more engine harmonics than the other 2 low class car companies.

 

The link below from Post #3469 shows the damper for the 2015-2017 Mustangs. Scroll down to the bottom of the page to see what Mustangs it fits - which shows all models from 2015-2017.

So why is Ford showing this damper fits 2015-2017 Mustangs if not all of them came with this part from the factory? That's why I'm wondering if it's part of some "fix" Ford has come up with along the way.

https://parts.levittownfordparts.com/oem-parts/ford-damper-fr3z4a263a

Number 12 is the damper weight, and number 13 is the longer subframe mounting bolt.
https://dz310nzuyimx0.cloudfront.ne...76f4c7da/c117eb033f0df6ec518848f201a4d964.png

 

Finally,
174 pages and about 3475 posts later a OEM part surfaces that address harmonics.
I've learned the S550 platform is very sensitive to pinion and trans angle, the old school thought of
"Get it to within 1.0 deg. and call it good" We can all forget about that philosophy. A few 1/10's of a deg. is more appropriate, then call it good.
One other thing, the transmission output and differential pinion are offset from center / right, so when guys state some vibration issues cleaned up after the rear cradle was squared up, that logic stands to reason. The transmission drive axis and pinion axis from center / right have to be parallel with one another. We're dealing with a platform that has a compound angle driveshaft.

I ordered up the 2018 rear dampener counter weight. I'll post feed back after a few hundred miles.

This has been an exhausting thread, I'm grateful to the one's who have stuck it out to arrive at answers Ford couldn't figure out on their own.

 

my problem went away after a drive shaft replacement. A few thousand miles later and my pinion bearings in the differential went bad. They rebuilt the differentials, about 100 miles later shes vibrating pretty good between 60-70mph. Had my tires check for balance (never had tires balanced this often on a car lol) and sitll doing it. So i guess its going back to the shop.

Guys I loved ford, and mustangs but im coming near an end here. Though i bought it CPO there is some wiggle room for Lemon Law which I might try. Putting the exhaust back to stock and going to start looking into something else. Best of luck everyone. Ill tyr to update this once i figure everything out.

 

Sorry to hear this, i reallly love the the look of the car and the 2018 just doesnt look as good imho. Hopefully someone in the aftermarket will step up and help us guys out. This really isnt acceptable for a car this expensive . These vibes are not good for any of the drivetrain. I am going to be getting a ATI balancer to see if its mabe related to engine harmonics.

 

I agree. I think the vibrations are what caused the pinion bearings to prematurely fail, but i have no proof of that just some logic.
I typed up a good letter to mail certified to Ford for a buy back, and all details of visits etc.
Ive been to a dealership over 8 times in a year. I do expect Ford to deny this. but i have it in writing, before i go to the next step.

I agree, dont like the 18+ look. Its the 15-17 that really do it for me. I contemplated buying another one, but i'd be foolish to do that. I know someone here had this issue, and literally got another 17 GT, I wonder if he has had any major issues with it

 

The dampers were for the Ecoboost 2.3L's, not the GT's. My 2016 GT does NOT have any dampers on it stock. My 2016 Ecoboost 2.3L Base had them stock. The pinion flange is unique to the GT Manual.

I've had the IRS off entirely (dropped the whole thing) on both my GT and Ecoboost (for different reasons) so I've seen them in great detail. I had to remove the diff from both (again for different reasons).

With the EB I did a 3.73 Torsen swap, with the GT I sheared a diff bolt and had to replace the whole cover. Both were manuals with the MT-82. Both 2016's.

The Ecoboost/V6 manual, Ecoboost/V6 automatic and GT automatic all use a slightly different pinion flange than the GT Manual. Not sure why the GT Manual's pinion flange is unique, but there it is.

And I get a niticeable vibration around 115~120. But it doesn't occur at any speed below that. Not sure if it's drive shaft related or if it's wheel related. I don't recall ever having that vibration with my RTR Tech 7 wheels, so at this point I'm leaning towards the stock PP wheels / Pirellie Zeros being the source. If I find anything different I'll be sure to post it.

I'm not sure if the harmonic dampers will help GT's a whole lot, but maybe. They were there on the EB's but not the GT's, yet they use the same drive train, so I thought that a bit odd. Maybe they were not to dampen drive train harmonics, but engine harmonics.

The EB's have a harmonic balancer that weighs 18 lbs. It more or less is 180 degrees out of phase with the engine's natural resonant frequency. But when the engine isn't at it's peak resonant frequency, there are still harmonics occurring at a lower amplitude and frequency both from the engine and the harmonic balancer. So while the harmonic balancer cancels out the worst harmonics at it's resonant frequencies, which may be a certain range where it's more noticeable, it actually creates harmonics at other operating frequencies. This makes it "gritty" or "coarse" feeling, but somewhat consistent across the rev range instead of "it's smooth most of the time but always gets a little coars round x RPM". I'm NOT a fan of internal carriage type harmonic balancers one bit.

Crank pulley wheel based harmonic balancers are just weighted pulley wheels for the serpentine / AC belts. Kinda like a balanced wheel with weights on it to off-set any non-uniformity in the tire / wheel. So they address the peak resonant frequency (worst case) by counter balancing it, but they do not address any sub-harmonics in that range typically.

I'm wondering if those dampers are to reduce the sub-harmonics of the EB's. It's a "gritty" feeling engine for sure. Nothing like the buttery smooth 5.0L V8. In fact the 2.3L EB almost shudders around 2,000 RPM under load because you have only 4 cylinders firing in one combustion cycle vs. 8. So the time between torque pulses of each cylinder firing is double that of a V8 (aka the gap), making it very coarse feeling down low.

 

Check out this youtube video from Lethal Performance. How much the diff moves around is really concerning, well worth the watch.