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Grinding shifting into reverse.

The other day I noticed something strange when I shifted into reverse.



The other day I arrived at my usual parking lot and placed the gear selector in NO gear and released the clutch. I sat for a few minutes gathering my belongings and listening to the end of an NPR story. When the story finished I fully depressed the clutch and shifted into reverse to leave the car. When I pushed the gear selector into reverse my gears ground. I was astonished because I just had my clutch replaced within the past 3 months and I had been sitting on a flat surface without moving for at least 3 minutes. A little history, my reverse gear ground prior to getting the clutch replaced. It would grind when I would shift into reverse in nearly all settings.



Whats the deal?

Comments

  • edited March 2010
    If you pump the clutch peddle two or three or four times, and then try to shift, does it go into reverse without the noise? If yes, you may have a master cylinder or slave cylinder or air in the line problem. If no, it could be the synchromesh has broken on that gear train in the transmission. How old is your vehicle, have you had your transmission oil checked for metal flakes?
  • edited March 2010
    Try putting the transmission in reverse without the engine running. Does it shift right? If so, the problem might be with the clutch hydraulics.

    Reverse gear has no synchro. It's a straight cut gear. And if the clutch hydraulics doesn't fully release the clutch the transmission still spins. With no synchro in reverse the gear grinds. While in forward gears there are synchros involved. And this can mask a hydraulic clutch problem.

    Tester
  • edited March 2010
    Start the engine and put the transmission in first gear. There should be no grinding at all. Put the transmission in neutral, and without releasing the clutch pedal keep it in neutral for 10 seconds. That's 10 seconds in neutral with the clutch pedal all the way to the floor. Then put the transmission in reverse.

    If it goes into reverse with no grinding you have no problem at all. If it does grind your clutch is dragging, possibly the pilot bearing has failed or the clutch disk is warped.

    There's nothing unusual about the transmission grinding if you go directly into reverse from neutral. That's because, unlike all the forward gears, there's nothing on the reverse gear to keep it from grinding. I got into the habit of putting my transmission into any forward gear before putting it into reverse just do I wouldn't have to hear the noise.
  • edited March 2010
    This should not be an issue of the hydraulics -- unless my mechanic did a bad job -- because my invoice from the repair states the master and slave master cylinder were replaced. I know that once and a while I have trouble shifting into reverse with the engine off; if I shift into a forward gear it will fix itself. Is that a safe solution, as JayWB suggested?

    Thanks, willmoe
  • edited March 2010
    Jay is correct..There is no synchronizer on reverse gear. With the clutch engaged in neutral, the transmissions gears are spinning..if you quickly try and de-clutch and engage reverse, the spinning gears will clash. Engage another gear first, then slip into reverse..
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