• Sign Up! To view all forums and unlock additional cool features

    Welcome to the #1 Fiesta ST Forum and Fiesta ST community dedicated to Fiesta ST owners and enthusiasts. Register for an account, it's free and it's easy, so don't hesitate to join the Fiesta ST Forum today!


Is my diff defective?

Messages
69
Likes
13
Location
Los Angeles
#1
Hi guys,
I have a 2019 ST at about 9,300 miles. I have been starting to notice a meral geinding noise when making right turns that require a bit of grip (i.e. freeway on ramps and cornering in canyon driving) and it’s gotten noticeably louder recently. At first it sounded like something coming from my suspension decompressing and maybe a couple of bushings needed to be greased. But it’s become more of a rotating metal kind of clanging sound. I’ve checked the axle and half shaft and there isn’t any play or wiggle when I try to move them and all the rubber boots are intact. This leads me to believe my diff is grinding when taking right turns. I would bring my car into a dealership as it is under warranty still, however I have a tune from stratified (car only has an exhaust and gapped spark plugs) and I’m worries the technician will say it is due to the bump in torque and then not cover anything that is defective as well as charge me a diagnostics fee. Should I just keep driving it until it becomes un-driveable and swap an msport lsd out of pocket or take my chances and bring it to a Ford dealership? Any other ideas on what this noise could be and has anyone else experienced this? This car has seen two autoX days and lots of canyon driving, but it should take more than that to kill a brand new diff on a 9k mile car!!
 


Fiestig

Active member
Messages
754
Likes
781
Location
Pacific Grove, CA, USA
#2
Dealer would have to legally prove that the tune is the reason for the issue. Noise on turns would typically be a cv joint, but if it is at an extent that it is making driving difficult or unsafe, Just go back to stock tune and take it in (y)
 


Messages
445
Likes
520
Location
Metro Detroit
#4
IMO a differential would not be directional, the only change between right and left turns is the is the rotation bias between the two axles. I think you need to be looking at bearings, brakes (rotor slap) and CV joints. BTW, typically warped brake rotors can cause a vibration during braking. However I've see cars where the rotors were warped enough to contact the brake pads and NOT have a vibration in braking.
 


OP
J
Messages
69
Likes
13
Location
Los Angeles
Thread Starter #5
I just had the rotors resurfaced and put in new pads and SS brake lines about 300 miles ago and this started happening before then, so the brakes are pretty solid right now. But I think you could be right Scooter on it being a bearing or cv joint!
 


PunkST

2000 Post Club
Messages
2,239
Likes
1,413
Location
Menasha
#7
Clicking is a cv joint. Loud grinding when weight is transferred is a wheel bearing starting to go. Eventually itll howl all the time and then fail.
 


OP
J

jazz

Member
Messages
69
Likes
13
Location
Los Angeles
Thread Starter #8
No it’s definitely not tire rub, I’m also on stock wheels. And I don’t think it’s a wheel bearing because it’s not a consistent noise nor is it speed dependent. It only happens when the car is requiring more grip during turns and higher speed corners. Like it doesn’t happen when making a right turn on the street. But accelerating hard turning on an on ramp or taking corners hard and fast on a canyon road will make the grinding noise.
 


PunkST

2000 Post Club
Messages
2,239
Likes
1,413
Location
Menasha
#9
Which side is it coming from. You could be hearing the torque vectoring doing its job
 




Top