Vibration between 50 & 70 mph

[shahram72]

I just want to personally thank BMR Tech for chiming in here and helping. Our solution may have to come from the aftermarket. Going in Sat for my second driveshaft replacement.

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[keltymd]

Kelly,

Did you apply the below to the above during your research:

1) Car at full weight (driver and full tank of gas)
2) Car at relaxed weight (driver and gas tank almost on or at "E")


Won't the driveline angle will change or be affected dependent upon weight of vehicle (weighted, unsprung weight or during weight transfer due to momentum)?

Any change should be very minimal. With a SRA there is a lot of change but with IRS the diff is for the most part fixed.

 

[hungryhippos]

I can say after driving it a few days, it's not completely gone. I'd say 95% gone, but now I feel it in the gas pedal.

This is what I'm feeling. I'm ~800 miles in and started feeling pulsating at the gas pedal at ~55-62 then goes away. Is this the same problem or different?

edit: Mods below, i've only tested this in 6th gear (automatic transmission), gunna go take a drive and test 4 and 5 as well.

 

[keltymd]

I have improved vibes by pushing the rear of the cradle up, the front down and then shimming the trans cross member down.

I have yet to see any issues from it. But I'm going to be testing it rigorously.

Can I ask how you pushed the rear cradle up?

 

[speedfrk]

This is what I'm feeling. I'm ~800 miles in and started feeling pulsating at the gas pedal at ~55-62 then goes away. Is this the same problem or different?

edit: Mods below, i've only tested this in 6th gear (automatic transmission), gunna go take a drive and test 4 and 5 as well.

You're probably feeling engine vibration at this point. 60mph, 6th gear auto on an EB is really pretty low rpm and lugging the engine down. What rear end 3:15? I've done lots of testing at various rpms and it is a 4cyl engine that has it's rough spots.

 

[hungryhippos]

You're probably feeling engine vibration at this point. 60mph, 6th gear auto on an EB is really pretty low rpm and lugging the engine down. What rear end 3:15? I've done lots of testing at various rpms and it is a 4cyl engine that has it's rough spots.

So I'm going to rule out the engine because I just got back and the vibration in the pedal and steering wheel was constant between 5th and 6th. 3rd and 4th had the same vibration feel though I can't verify intensity due to the RPM's kicking up and adding their own vibration. It starts at 53mph and 65mph, tested with cc on and off, both D and S, and S for testing specific gears.

Honestly? I don't know if its 3:15 or 3:31. I assumed it was 3:31 since that's what is standard. I came home one night and it was sitting in my garage, my wife went off and bought it while I was at work. All i know that its a base ecoboost, no PP & 19inch rims. I'm gunna go find the paper work and confirm.

 

[GTP]

This is what I'm feeling. I'm ~800 miles in and started feeling pulsating at the gas pedal at ~55-62 then goes away. Is this the same problem or different?

edit: Mods below, i've only tested this in 6th gear (automatic transmission), gunna go take a drive and test 4 and 5 as well.

This is known as the CTP (Conservation of Technical Problems) syndrome.
Basically, you take your car in to service for one issue, which is resolved. But it comes back with another smaller problem.
You have to take your car back in successive times until your car ends up with a problem small enough for you to live with.

 

[Dave]

This is what I'm feeling. I'm ~800 miles in and started feeling pulsating at the gas pedal at ~55-62 then goes away. Is this the same problem or different?

edit: Mods below, i've only tested this in 6th gear (automatic transmission), gunna go take a drive and test 4 and 5 as well.

Probably different; mine starts at about 55 and stays until around 75+.

Smooth as glass at 80.

I have 3.35 gears and still feel it if I shift to 5th. The vibration changes slightly depending on how much I'm on the gas, or if I push the clutch in.

I would think as a general rule that the vibration characteristics changing with the clutch in or out would rule out tires but what do I know. :shrug:

 

[gov cheese]

Found a dealer that has the required MTS 4000 NVH analyzer listed in SSM #45938. Went in for the 50-70 mph vibration, my car starts around 55 and is pretty much gone after 70. Tech did notice the vibration during the ride along. During inspection DS was found to be defective and was replaced.

Still feeling the vibration not sure if the DS improved it or driving a crap rental car for a couple days is masking some of the vibration. I want to put some miles on the new DS before taking it back to the dealer.

BTW - Recommend going for a ride along with the tech and have them drive. Show them where and how the vibration is felt. In my car the vibration can't be felt until speed is maintained for a couple minutes. Vibration seems to build then starts to pulse a little like there is some sort of harmonic involved.

 

[keltymd]

well mine has been at the dealer for 4 days and a tech still has not even looked at it. Yeah Ford

 

[keltymd]

just dropped mine off today. yesterday they changed the oil (first change 2500 miles) and this morning I noticed it making a deep knocking sound not real loud but sounds like a main IMHO. Laundry list for them
1. Knock
2. vibration at 55 from drivetrain not tires
3. vibration at about 78 and up that responds to throttle input
4. drives door window sometimes grabs when you open the door.

I love mustangs but after the deal of having my 14 Track Pack rear end rebuild 5 times and two driveshafts to try and unsuccessfully fix it I told them if this one has huge issues Im buying a Lexus just to have a dependable car.

Well lets see
1. wont look at the knockvbecause I have a Bobs Oil Air separator
2 and 3 I have Steeda Shocks/Struts and the BMR CB005 lockout kit so they will not look at the vibration

but hey it only took them 4 days of keeping my car to tell me they wont look at it.

 

[theredmeadow]

Well lets see
1. wont look at the know because I have a Bobs Oil Air separator
2 and 3 I have Steeda Shocks/Struts and the BMR CB005 lockout kit so they will not look at the vibration

but hey it only took them 4 days of keeping my car to tell me they wont look at it.

it took them 4 days to road force balance my tires. and probably could've kept it longer but i kept calling to get a status and after 4 days and 1 thing done I had to get it back.

 

[BMR Tech]

I have improved the NVH with my stock DS on my new 2016 GT PP by:

-raising the rear of the IRS cradle .250" by removing the sag in the rear bushings

-dropping the front of the IRS cradle down .551" via shims

-dropping the transmission angle down, by shimming the cross member down .250"

This has resulted in the best working angles I have found, basing the results strictly from driveline angles and how they relate to the NVH of the driveline at multiple driving speeds.

The above has placed my engine/trans angle down 3.5~degrees, and the rear pinion flange angle up about 2.9~degrees.

Now, I have not had much time to test this modification for durability, or for negative consequences, or ill wanted suspension geometry changes - as I have been simply working to improve the NVH that I believe is affiliated with the driveline due to what I believe to be poor working angles..

 

[keltymd]

I have improved the NVH with my stock DS on my new 2016 GT PP by:

-raising the rear of the IRS cradle .250" by removing the sag in the rear bushings

-dropping the front of the IRS cradle down .551" via shims

-dropping the transmission angle down, by shimming the cross member down .250"

This has resulted in the best working angles I have found, basing the results strictly from driveline angles and how they relate to the NVH of the driveline at multiple driving speeds.

The above has placed my engine/trans angle down 3.5~degrees, and the rear pinion flange angle up about 2.9~degrees.

Man i hope a lot is around the corner for the rest of us. Good work sir

 

[ABS550]

Found a dealer that has the required MTS 4000 NVH analyzer listed in SSM #45938. Went in for the 50-70 mph vibration, my car starts around 55 and is pretty much gone after 70. Tech did notice the vibration during the ride along. During inspection DS was found to be defective and was replaced.

Still feeling the vibration not sure if the DS improved it or driving a crap rental car for a couple days is masking some of the vibration. I want to put some miles on the new DS before taking it back to the dealer.

BTW - Recommend going for a ride along with the tech and have them drive. Show them where and how the vibration is felt. In my car the vibration can't be felt until speed is maintained for a couple minutes. Vibration seems to build then starts to pulse a little like there is some sort of harmonic involved.

Have a look at my posts 1767 (on page 118) and post 1773 (on page 119).
I wanted to take the guess work and subjective part out of the equation, so I purchased this Audio Spectrum Analyzer for just a few bucks from the App Store. The problem is shown very clearly on the screen, as is the result from my at-home DS balance. It's a very small investment which could help your dealership visit a success.

Cheers

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