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about gear box

Discussion in 'Automotive Electronics' started by hispeck, Jan 22, 2016.

  1. hispeck

    hispeck New Member

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    i want to ask, can manual gear box select without oil? am asking because i have one that is not selecting gear when the car is on, i have done almost everything, it all started after the plate went bad, i re-kited it and it worked, after then i started experiencing this problem of not entering gear when the car is stemming, i have changed the disc twice the same thing, but i just found out that there is no oil inside the gear box, so i ask can the oil be responsible for the problem?
    hispeck
     
  2. alec_t

    alec_t Well-Known Member Most Helpful Member

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    I'm afraid I can't understand much of your post, but lack of oil is a no-no for a gearbox. It could prevent the synchromesh working properly, which in turn could result in difficulty in engaging a gear, and it will cause accelerated wear and damage to the gear teeth.
    What has this to do with automotive electronics?
     
  3. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    1) Yes, a gear box will shift if there is not the correct amount of oil in it. If there is absolutely no oil in it and a gear has become stuck on a shaft or the shaft stuck, then it won't shift, but that scenario seems unlikely and is refuted by the fact that you can shift when the motor is off. There are lock-out pins in some transmissions that are there to prevent you from doing something like shifting for 3rd gear to reverse. I have not worked on a modern (i.e., post 1986) manual transmission, but it is conceivable that such lock outs could be electronic in newer transmissions.
    2) Many cars have a hydraulic clutch that works the "plate" you describe. Be sure that clutch is working. In my experience when the hydraulic clutch went out on my car, once moving, I could still shift carefully. Again, a modern car may have an electronic lockout to prevent you from doing that -- I just don't know. This comment,
    makes me wonder if your problem is really in the clutch not properly disconnecting the engine from the transmission. If the car is standing still with engine off, put it in first gear, press the clutch in and see if you can start it. Of course that was the way we "jump started" cars many years ago. If the starter won't do anything in the test described, then there is an electrical interlock to sense neutral. How old is the car? Does it have a "computer." If it has a computer, I reluctant to suggest what you can to, as there is a chance it will affect the computer. If it doesn't have a computer, let us know.
    3) Even if the clutch is entirely mechanical, there will be linkages. It is still worth doing the test I described in #2 to see if the clutch is properly disengaging.
    4) As for your final question, be sure to add the correct amount of the correct grade of oil to the transmission. The fact that you can shift with the engine off tells me the gears and /or shafts are not frozen. They may be damages from lack of oil, but that is another subject.

    In summary, my first guess is that your clutch is not properly disengaging or that there are interconnects, either mechanical or electrical, that are preventing the clutch and/or shifting once the motor is running. See suggestions #2 and #3.

    What make, model, and year car is it?

    John
     
  4. dave

    Dave New Member

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  5. hispeck

    hispeck New Member

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    Thanks john, the car is Honda accord 94, some still say is from disc but i don't know
     
  6. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    Do you have the service manual? If not, here is a link: http://www.wedophones.com/Manuals/Honda/Honda Accord 1994 - 1997 Service Manual.pdf

    I took a quick glance at it.
    1) Your clutch is hydraulic. Be sure there is fluid in the master cylinder,
    2) With engine off, check to see whether the clutch release arm moves when someone presses the clutch. In many cars, you can shift without the clutch when the engine is off. Of course, if it doesn't move, you have found the problem.
    3) Your car has an ECM. Jump starting a car like that or jumpering across the solenoid is at your own risk. You can easily damage the ECM.
    4) There is a clutch switch right above the pedal. That usually only prevents the car from starting with the pedal not pressed. It doesn't actually detect whether the clutch is released. You could try starting the engine with the car in 1st gear and clutch pressed. If the car jumps, you know the clutch is not releasing.
    5)There is a vehicle speed sensor (VSS) plugged into the transmission housing. Be sure that is plugged in. Not sure whether it will affect anything, probably not, but why worry.
    6) Your transmission takes 10W-30 or 10W-40 engine oil, SF or SG grade or better.

    I used to be much more involved with cars than I am now, but I am still interested in the solution, when you find it.

    John
     
  7. hispeck

    hispeck New Member

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    Thank you very much John, i have tried to start the car with first gear on but the car keep jumping , you really understand my problem, please what should i do as is not releasing?
    hispeck
     
  8. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    Have you checked to see that the clutch line is connected and its reservoir is full of the correct hydraulic fluid? Hydraulic clutches work much like brakes, but in reverse. When you press on the clutch pedal it releases the clutch pressure. The pedal should feel a little like a brake pedal feels. With the car properly raised and on blocks, have someone check the action of the release lever while another person presses on the clutch pedal.

    1) If the lever doesn't move very much or at all, and the pedal presses easily to the floor, you probably have a problem with the clutch hydraulics, like a bad master cylinder, a disconnected line, air in the line, or no hydraulic fluid. Did you bleed air from the line when you reassembled the clutch?

    2) If the lever doesn't move, and the clutch pedal feels normal, then I would suggest trying to move the lever manually at the clutch/bell housing. It should be hard to move, so I would clamp a steel bar onto it to help move it. If you can move it manually, you may still have a problem in the hydraulic system for the clutch (see #2).

    3) If you can't move it manually or the pedal feels very stiff, then the problem may be in the assembly of the clutch. Be sure the throw-out bearing is in good shape (they can freeze on the shaft), the parts are assembled in the proper sequence, and the forks from the clutch lever are properly engaged with the throw-out bearing. Remember, if the lever can't be moved at all, you should also feel a lot of resistance when you press on the clutch pedal. If the pedal feels normal, you may also have a hydraulic problem.

    Good luck.

    John
     

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