does your gearbox crunch going into reverse
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Thread: does your gearbox crunch going into reverse

  1. #1
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    does your gearbox crunch going into reverse

    i know mine does and few others that ive heard to more so the F20's.
    is this just another characteristic of the car?

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    ive got a f16c box. it sometimes crunches in reverse, it usually does it when i try to put it in reverse and it wont go at all, i "pump" the clutch a couple of times and put it in again and it'll crunch.

    syncromesh worn???

    low oil level in box??

    no idea meself...

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    Checked the position of the clutch pedal?
    I had that on my F13. Just needed clutch cable adjusting at gearbox end. Presume it's the same for F20's.

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    I very occaisionally get it in my astra (F20), reverse is a straight cut gear so I wouldnt worry too much about it, no amount of adjustment will cure unless its doing it everytime.

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    Re: does your gearbox crunch going into reverse

    Originally posted by jamie_gsi
    i know mine does and few others that ive heard to more so the F20's.
    is this just another characteristic of the car?

    My F25 does sometimes.

    Vauxhall Says:

    "Engage gear with vehicle stationary 3 seconds after declutching."



    Being straight cut reverse doesn't take kindly to either the output shaft or input shaft moving at different speeds.
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    Mine crunches half the time.

    It doesn't do it if you declutch before you put it in (oooeerrrr)
    I have become comfortably numb....

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    f16cr and mine does it unless you stamp on clutch wait for engine speed to die right down (as in wait 3 secs) and declutch.

    i think most boxs do / will uless your really slow and carefull with it

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    i have an f20 box and have a had new clutch and adjusted it all over the place and it made no difference, had the gear box checked and its fine, have been told that reverse gear has always been a bit of problem due to the short shift, i have found the easiest way round it was to put it into first gear first, then put it into reverse it never crunches then. if it continues to crunch then you have a gear box problem, either syncromesh or selector or clutch cable needs adjusting.

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    Originally posted by AstraMad4It!
    i have an f20 box and have a had new clutch and adjusted it all over the place and it made no difference, had the gear box checked and its fine, have been told that reverse gear has always been a bit of problem due to the short shift, i have found the easiest way round it was to put it into first gear first, then put it into reverse it never crunches then. if it continues to crunch then you have a gear box problem, either syncromesh or selector or clutch cable needs adjusting.
    Don't want to upset you chap, but the whole piont is it is a straight cut gear and has no syncromesh on it.

    The clutch dragging could cause a crunch every time, but then it would crunch into first at times too then.
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    My F20 can crunch aswell.

    About 80% of the time you don't hear a thing but other times you could wake the dead with the noise.

    For some strange reason I can 'tell' when it's going to crunch into reverse, I grit my teeth and wait for the noise.....

    MattJ

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    mark touched on the problem. When the clutch is missadjusted it still slightly drags on the cover and flywheel which keeps the assembly spinning in the same direction as the engine. Then when you try reverse your asking a gear spinning anticlockwise to engage with a gear that is stationary and which also, as mentioned, is straight cut. You will get the same problem sometimes with a properely adjusted clutch, simply because of momentum and teh gear sets still spinning from whenever you were last in a forward gear. This comes back to marks "wait 3 seconds" quote.

    CCCCCRUNCH

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    Mine never crunches. It did when the clutch was set to bite "too low", so quickly adjusted clutch and it was fine. I just make sure I have stopped and the revs have died down (hence clutch engaged), then into gear no worries.

    Cars with cr@p gearboxes e.g. Fords seem to crunch a lot easier.

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    mine does at times too. I've learnt to wait for 1-2 seconds before engaging, though it still does alittle at times.
    Control is nothing without Power.........

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    as far as i know, later boxes had a brake type device to assist reverse selection.

    you do need to be stationary when going for reverse though, regardless.
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    Mine used to crunch regularly until found that.....

    If i stop completley and put in neutral, pop it into 3rd then stright round into reverse it never ever cruntches.

    Honestly, works every time for me!

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    thats alot to do!lmao
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    Re: does your gearbox crunch going into reverse

    i know mine does and few others that ive heard to more so the F20's. is this just another characteristic of the car?
    Yes mine did too for about 4 years until I got the clutch changed and it has been ok since then (apart form a few crunches).

    The F20 has always been know for crunching in reverse becaseu its stright cut and not syncomeshed. But it shouldn't 'always' crunch when you try to engage it.

    Do the following first
    1) check that clutch pedal is higher than the brake pedal. If not, adjust clutch cable.
    2) Put the car in reverse first, then start the car.
    3) before engaging reverse, select 1st then reverse. As the prblem gets worse you'll have to select 1st then 2nd then reverse.
    4) keep the box in neurtral for a bit longer before engagin reverse.
    5) check the gear lever linkage in the enigne bay.

    If parts 2,3 and 4 seem to happen alot, then your clutch is getting thinner.

    What happens is that when your in neurtral or you have the clutch pedal down, the clutch comes away from the flywheel. This means that the internals of the gearbox slows down and you can select reverse without crucnhing.

    Slecting foward gears ins;t a prblem as they are syncomeshed.

    Anyway, becasuse the clutch is thinner, even in neutral or with the clutch pedal down, the clutch is still in contaxct with the flywheel a little bit and hence the internals of the gearbox are still rotating. So when you select reverse, it crucnhes.

    So I got a new clutch fitted (Turbo item by LuK), 2hrs labout for 320. My gearbox had to come off so it was more expensive.

    If you car is < 1993 then it can be changed via the small access slot in the gearbox bell cover.

    > 1993 you can't becasue they changed the thikness to the flywheel, hence you can't squaeeze the clutch out or in, the gearbox has to come away form the enigne.

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    Agree with Oddball. My 1.3 doesn't crunch as long as I'm sensible, ie make sure car isn't moving forward. If in hurry, stop the box by selecting 1st (as mentioned elsewhere, but not a good habit).
    My 2 litre cav always crunched and had a stiff gear change cos cable had stretched. 4-5 turns on clutch cable and was good as new!
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    mine does so occasioanlyly when icannot be arsed to put the clutch fully down!!

    otherwise its ok
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    me always select 1st right before engaging R...never crunches then...
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    Originally posted by super__dan
    Mine used to crunch regularly until found that.....

    If i stop completley and put in neutral, pop it into 3rd then stright round into reverse it never ever cruntches.

    Honestly, works every time for me!

    Dan
    Does for me too..If I don't it'll crunch everytime.
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    My f18 (SRi 16v) can be hard to get in reverse.

    I found the solution is to rev the engine to about 3kRPM then try reverse, goes straight in.

  25. #24
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    jason, doesn't it crunch even harder when u stick into reverse with 3k on the dial??
    Control is nothing without Power.........

  26. #25
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    you do need to be stationary when going for reverse though, regardless.

    THATS why mine crunches when i use reverse to slow down on the motorway!

    Chip

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