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Some car advise needed (transmistion on dihatshu)

Discussion in 'The Pub' started by Zbike, Jul 25, 2007.

  1. hey im buyin a car for my gf i found wat i think is a good deal a 1994 dihatsue appluase with 140,000 ks and in good condition pwr steering automatic air con.

    My only problem is that the engine vibrates significantly when in gear and in idle. The vibration goes away once u accelarate in gear or when the car is in nuetral.

    My theory is once u put it into gear (drive) the transmition engages the motor putting stress on it thus lowering the RPMs cuaseing the motor to vibrate as it is idling too low.

    My question is what exactly is going on in the gear box to cause the vibrations (as i have little idea of how a automatic works). I know to an extent this is normal as several of my bikes and do something very simmilar.
    I want to know what is wearing out in the gearbox and how much would i pay to replace it (i know reebuild is about $800) but more importantly how long u can leave this unchecked without doing anything.
  2. Sounds like the idle is set too low on the engine. When you engage a gear, the auto loads up the engine and can cause these vibrations due to too low an idle speed.
    Try braking with the left foot when in gear, and bumping the idle up with your right foot a little, if it goes away, buy the car and get a tune up.
    This is NOT a gearbox issue.

    Regards, Andrew.
  3. Idles sounding too low sounds likely. Is it worse with the A/C on?

    Also, theres lots of similar siymptoms. There could be something wrong with the torque converter or clutch packs, or it also could sound like a bad engine or transmission mount or even a minor misfire.
  4. yeah i first suspected low idle.
    Its got EFI dont suppose they have adjustment screws for idle?
  5. yeah they do.

    How low is the idle btw?
  6. sorry to say i dont rember around the 1000RPM mark,(i know thats not saying much)
  7. Well, 1000 is not low for a car, even a small engine car like a charade.
  8. you need to look at what the idle is when the car is in gear. about 800 plus minus 150 is about right. you will find 2 adjusters on the throttle body one for the base engine speed and one for an air bypass. both of these will have an effect on the roughnes though just increasing idle will smooth things out. other issues could be and engine or gearbox mount but unlikely given the power. an injector clean and tune would be advisable given the klms. it dosnt sounnd like a transmission problem like a converter or clutches as they normaly show problems undr load.
    Good luck
  9. thanks for the info, appreciate it,
    will be having another look at the car later on.
  10. It is not as simple as just turning the idle screw to adjust the idle speed.
    The the idle speed actuator / air bypass valve may need cleaning / adjusting / replacing. It may have a faulty or out of adjustment closed throttle switch or throttle position sensor. Take the car to someone who knows what they are doing to have it fixed as all EFI cars have a different procedure for adjusting the base idle speed. When I was working at a Hyundai dealer we would get on average 1 car a week for the base idle to be adjusted after someone had tried to have a go themselves.