1. Introducing the smashing new Team FIAT T-Shirt !! To order yours click here : Team FIAT T-Shirt

Karrrr sound and jerk when applying reverse gear.

Discussion in 'Engine Compartment' started by nitinkumardba, Mar 18, 2011.

  1. fiatlover

    fiatlover Esperto

    Messages:
    1,599
    Bangalore/Kasargod
    Bangalore
    Grande Punto 1.4
    Get it checked. It could be a clutch issue. There could be issues that you can live with, but clutch problem is not one such. Check it at the earliest.
    I dont think think noise during shifting to reverse is normal. There can be noise if you do not fully depress the clutch while shifting. If you dont check it on time, you could end up shouting at FIAT for a break down.
    The car only give only indications. Not the damage always or absence of it.
    2 people like this.
  2. PatchyBoy

    PatchyBoy Esperto

    Messages:
    2,438
    Bangalore
    Who has the time to read it? I will try and find out for myself, or post in TFI full of experts. If nobody answers, then I will take on that role and dole out advice to others who have the same issue. If I cannot resolve the problem, then blame FIAT :D. But no sir, I will not read that stupid book. The guys who wrote it know nothing about cars :A

    Rajan
    1 person likes this.
  3. zenwalker

    zenwalker Esperto

    Messages:
    2,150
    Bangalore
    When i had reported this in my ownership thread, i was told by many that its ok. I mean your at halt, put reverse gear (full clutch depressed) some times sounds krrrr but immediately put the gear to neutral and put it back. So i have been practicising the same. Thought it doesnt happen alot. Once a while. Ill report it during my first service.

    If done during a run, yes it is. But at halt it happens though full clutch is depressed as said above. I do wait atleast for a second before engaging the gear.

    Oh btw, Some people just have an opinion for simplicity sake that others dont read manuals at all. :uh Starting to wonder if they ever try to allow a tiny gap to change their perception.
    Last edited: Sep 3, 2013
  4. Ganges

    Ganges Esperto

    Messages:
    3,122
    Driver Seat _/
    :
    Grande Punto 1.3
    i too had that noise when my car was 250 Kms old and the sound still comes after 77000 Kms too(yesterday while taking a reverse),its just human error.
    Dont give a thought.
    Take it as Normal and enjoy your garuda vahanam.
  5. zenwalker

    zenwalker Esperto

    Messages:
    2,150
    Bangalore
    I am sorry ganges, if full depressed as stated, still how come its a human error?
    As fiatlover says, did you checked with FASS? What they had to say?
  6. GP_Freak

    GP_Freak Amatore

    Messages:
    240
    Chennai/Madurai
    Chennai
    Linea 1.3
    I have this issue in both the Fiat and Martuthi. Its not user error. But not depressing the clutch fully also contrbutes to it. If the synchro doesnt engage properly, this issue happens for all gears. Under these circumstances, just double declutch and go to reverse.

    Edit: Not sure if reverse gear has syncros.
    Last edited: Sep 3, 2013
  7. Ganges

    Ganges Esperto

    Messages:
    3,122
    Driver Seat _/
    :
    Grande Punto 1.3
    i never took it as an issue,at the end of the day the reverse gear works for me.
  8. zenwalker

    zenwalker Esperto

    Messages:
    2,150
    Bangalore
    Correct, even myself took it that way but few posts here happen to suggest otherwise that it could lead to much different problem. Hence was wondering if you happen to take it to SC.
  9. Mohankv

    Mohankv Amatore

    Messages:
    248
    bangalore
    Try engaging the reverse gear after u come to a complete halt cos even if you are start to roll forward or back while u engage reverse this noise and jerk happens.
    Last edited: Sep 3, 2013
  10. PatchyBoy

    PatchyBoy Esperto

    Messages:
    2,438
    Bangalore
    OK. Let me try to explain a bit more technically:

    Manual transmissions use mostly helical gears, but reverse is a special situation that requires a different type of gear - a spur gear. The gears that make up the forward gear ratios are all helical gears. The teeth on helical gears are cut at an angle to the face of the gear. When two teeth on a helical gear system engage, the contact starts at one end of the tooth and gradually spreads as the gears rotate, until the two teeth are in full engagement. This gradual engagement makes helical gears operate much more smoothly and quietly than spur gears. Also, because of the angle of the gear teeth, more teeth are in engagement at any one time. This spreads the load out more and reduces stresses.


    The only problem with helical gears is that it is hard to slide them in and out of engagement with each other. On a manual transmission the forward gears stay engaged with each other at all times, and collars that are controlled by the shift stick lock different gears to the output shaft. The reverse gear on your manual transmission uses an idler gear, which has to slide into mesh with two other spur gears at the same time in order to reverse the direction of rotation. Spur gears, which have straight teeth, slide into engagement much more easily than helical gears, so the three gears used for reverse are spur gears. Each time a gear tooth engages on a spur gear, the teeth collide instead of gently sliding into contact as they do on helical gears. This impact makes a lot of noise and also increases the stresses on the gear teeth.


    With the clutch fully depressed and the car stationary, the reverse should engage noiselessly. However, if you are experiencing a whirring noise, each time you try to slot into reverse, there is a problem with the set up and needs to be attended to by an expert mechanic.

    Having said that, if you hear a whirring noise occasionally, then it indicates 100% human error and your driving style needs correction.

    Rajan

    PS: @Zen - my perception is based on experience and I know for a fact that the vast majority of the car buying populace do not read the manual thoroughly. By your own admission, it includes you.
    Last edited: Sep 3, 2013
    2 people like this.

Share This Page