Vibration between 50 & 70 mph

[amilhazes]

Lol funny you mention that. That's the biggest factor for a lot of return customers and also quality control.

Sent from my SM-N920T using Tapatalk

I just wish they were transparent. Be honest. Don't lie to me and insult my intelligence by telling me the vibrations I'm felling in the very specific speed window of 50-75mph are being caused by my exhaust, or the "poor welding jobs". Like come on. I told the tech the issues were persistent long before I had my Roush's installed. No reply yet...

Sponsored

 

[69mach1-395]

Maybe. But it's also not normal. And NOT from my Roush exhaust. So dunno what their excuse is for "can't find anything wrong"

Agreed, not exhaust related either. It's usually wheel balance or front bearings.

 

[amilhazes]

Lol funny you mention that. That's the biggest factor for a lot of return customers and also quality control.

Sent from my SM-N920T using Tapatalk

I will say received a call from FCSD within 24 hours of sending an escalation with Deysha here in the forum. Was very impressed with rep's promptness and enthusiasm toward wanting to help with my problems.

 

[GT Pony]

Maybe. But it's also not normal. And NOT from my Roush exhaust. So dunno what their excuse is for "can't find anything wrong"

What's it do on a smooth road if you run it up to around 80 MPH, then pop it into neutral and let it coast down to 50?

 

[amilhazes]

What's it do on a smooth road if you run it up to around 80 MPH, then pop it into neutral and let it coast down to 50?

Smooth up top at 80+. Then during decel vibration comes in, I can't remember the peak mph where it was most prevalent, but then once the car drops into the 40's it just disappears.

 

[GT Pony]

Smooth up top at 80+. Then during decel vibration comes in, I can't remember the peak mph where it was most prevalent, but then once the car drops into the 40's it just disappears.

But did you try that test with the transmission in neutral, or still in gear?

 

[amilhazes]

Honestly I can't remember. I haven't had my car for a couple weeks, and I stopped doing driving tests a while before that because it would upset me so much

 

[GT Pony]

Honestly I can't remember. I haven't had my car for a couple weeks, and I stopped doing driving tests a while before that because it would upset me so much

Try the coasting test when safe to do so. It will take out any engine or exhaust induced vibrations if they exist.

 

[amilhazes]

Try the coasting test when safe to do so. It will take out any engine or exhaust induced vibrations if they exist.

Tell my dealer that. ;-)

 

[GT Pony]

Tell my dealer that. ;-)

If you find that the vibration goes away when doing the coast down test, then that's definitely something you would want to tell your dealer. They might not even think of doing something like that. :shrug:

 

[amilhazes]

If you find that the vibration goes away when doing the coast down test, then that's definitely something you would want to tell your dealer. They might not even think of doing something like that. :shrug:

The guy who is helping me out there is on the forum and we've been messaging. I sent him the suggestion.


I just feel like...

Get a mustang they said. Put an exhaust on it they said. Won't affect your warranty they said. They have to prove your parts caused the issues they said... Haha

 

[Cobra Jet]

Fellas -

More so, the new guys who just came into the forum or this thread - if your Dealership (Ford Service Center/FSC) is giving you grief that they "can't find or figure out" the vibration issue - all you need to do is print out my post # 1037 from this thread. It contains the events that led to my driveline fix AND the entire conversation for resolution and parts diagnosis/replacement via direct communication between my FSC, the Ford Engineer who went to the site and the Ford Engineers located AT FORD.

Show your Service Manager those pages 1-10 that I put in that post 1037 - and tell him to put his BEST TECH on the job...period!

It will speed up their diagnosis process IF they FOLLOW those docs.

One more thing:
Don't let ANY FSC Service Manager or Tech tell you that a driveline vibration is a normal characteristic of the Mustang - it is NOT.

The common characteristic of the driveline vibration is it comes on right around 55+mph, gets somewhat worse around 65mph and could level out beyond 80mph. If you get the car up to speed you'll feel there's almost no vibe up to about 40-50mph.

Tell your Tech or Service Manager to go for a ride with you - a LENGTHY ride, not some damn ride in stop and go traffic for 1 mile!!! Take it on a highway where you can cruise it! The car HAS to maintain speed within the "vibe zone" so they can actually confirm what you are feeling - also tell them to coast it down from 65mph to below 45mph and bring it back up to 55mph. Go for a 20min drive - I'm not being sarcastic at all - THAT is the only way to really feel and diagnose the vibe.

If they insist it's "normal", go to another FSC.

Good luck!!

(PS - if you haven't read post 1036 or 1037 by me, you're missing really informative details that will surely help your situations!)

 

[amilhazes]

Fellas -

More so, the new guys who just came into the forum or this thread - if your Dealership (Ford Service Center/FSC) is giving you grief that they "can't find or figure out" the vibration issue - all you need to do is print out my post # 1037 from this thread. It contains the events that led to my driveline fix AND the entire conversation for resolution and parts diagnosis/replacement via direct communication between my FSC, the Ford Engineer who went to the site and the Ford Engineers located AT FORD.

Show your Service Manager those pages 1-10 that I put in that post 1037 - and tell him to put his BEST TECH on the job...period!

It will speed up their diagnosis process IF they FOLLOW those docs.

One more thing:
Don't let ANY FSC Service Manager or Tech tell you that a driveline vibration is a normal characteristic of the Mustang - it is NOT.

The common characteristic of the driveline vibration is it comes on right around 55+mph, gets somewhat worse around 65mph and could level out beyond 80mph. If you get the car up to speed you'll feel there's almost no vibe up to about 40-50mph.

Tell your Tech or Service Manager to go for a ride with you - a LENGTHY ride, not some damn ride in stop and go traffic for 1 mile!!! Take it on a highway where you can cruise it! The car HAS to maintain speed within the "vibe zone" so they can actually confirm what you are feeling - also tell them to coast it down from 65mph to below 45mph and bring it back up to 55mph. Go for a 20min drive - I'm not being sarcastic at all - THAT is the only way to really feel and diagnose the vibe.

If they insist it's "normal", go to another FSC.

Good luck!!

(PS - if you haven't read post 1036 or 1037 by me, you're missing really informative details that will surely help your situations!)

The service tech I check my car in with has read this entire thread..

 

[Lo Pony]

The service tech I check my car in with has read this entire thread..

You have an "enthusiast" technician. You are one of the lucky ones!

 

[Lo Pony]

If anyone is interested in working on this problem yourself, PM me and I will guide you step by step through the troubleshooting process.

Having solved this problem myself on a 99 Cobra with IRS, and helping countless others on their cars, I can tell you definitively that you can at least improve it and potentially eliminate the vibration completely. It will involve field balancing through trial and error. The repair is not a band-aid. It is a permanent fix that will not compromise the durability or safety of the drivetrain in any way.

There are no parts to buy. Here is what you will need:

-A lift, or at least a good jack and a sturdy set of jack stands
-Floor creeper
-A dial indicator with a magnetic base (borrow one, or go to Harbor Freight or NAPA tools)
-Sockets and wrenches (air tools are great)
- machine washers for the pinion flange bolts.

That's it. Let me know. I'm ready to tackle this problem myself on my car.

Sponsored