2011 ford fiesta se 1.6 need help car is bucking

[Zflockaa]

http://imgur.com/a/Qc2AqFx

I dont know what is happening is this due to the transmission? Need help please

 

[scotman]

This fiesta has which transmission? You don’t mention that.
The bucking is occurring at all speeds? Only below 35 mph? It’s worse when you start off with a cold engine? The hesitation in drive axle rotation says less to me than the clattering noise. It’s very difficult to visualize the situation without having more information.

 

[Handy Andy]

In seeing the above and the repetitive clack/grind sound - the transmission noise can be from the solenoids needing a new clutch pack or your differential needing some service - or anything in-between.

Brakes, er no - but there is a thread that might give you some direction as to how to determine the surging effort.

https://www.fordfiesta.org/threads/mot-help-plz.8667/post-22906

Another that deals with how to diagnose your transmission - if you have the "sport transmission" where the shifter shows PRNDS versus PRNDL - then the test may not apply to you. They did up a transmission with solenoids but how the system interacts with your Handbrake or Emergency Brake - by lifting up that handle - can help you listen for noises and feel operation that you might miss otherwise.

https://www.fordfiesta.org/threads/...3-fiesta-sticks-while-driving.8383/post-22877

The above is test method to see if you can make the car roll but not accelerate when you place it in Drive but - stay at idle speed and creep along once the transmission is engaged and it should not make that clacking/rattle sound nor surge.

The test is to see if the system knows how to stop or release the solenoids so it can coast or move properly it uses the wheel speed sensors to figure this out.

• - then if that test fails
  • - you may have an issue with idle to wheel speed
  • - which may mean a bad wheel speed sensor
• - you have to do the test described above - on an open parking lot to let you watch for surging and listen for these noises as well as see if the speed stays constant and doesn't accelerate
• - if the brake then is applied thru the brake handle (handbrake is gently pulled up to light the light BRAKE - letting the PCM see the BRAKE light on to let it process the stopping effort before the shoes contact the drum)
• - the noise clacking should cease
  • - if it does, then it's a good bet that the solenoids and the clutch pack need service.
  • If it does not, then the transmission has internal damage and or is dry, no matter what, it needs service.

The original intent of that thread was to help offer a means to test your brakes and to check for dragging - which if the handbrake is not properly tensioned or too tight (lifting the handle - engaging the rear brakes before the first detent, for example, means the cable is too tight and needs to be slackened) - the rear drum brakes will drag all the time and cause premature wear on the driveline - let alone the rear wheel tires.

Were, are or was any evidence of leaking fluid present? Might disclose a bad seal and now the housing is getting dry.

However, surging? Then the noise is more specific to a type of solenoid operation I'd hear when you first roll the car and it has to start the process rolling - that is a freeplay sound of a clutch pack that is nearing the end of it's life, the rattle is the "length of throw" the fingers have to apply in distance and in force - against the clutch and plate to engage while the car tries to stabilize the motion and idle speed. Not unlike how you pop release a clutch to engage the driveline - in 1st Gear - - gently applying the clutch you won't hear this noise because the clutch is being linearly applied, not thru a digital solenoid driver mechanism making the rattle.