Grey

iTrader: (61)

When I changed my sister's oil I went to check for leaks so I started the engine with the front wheels still off the ground. I had the car in neutral and I see that the front tires are spinning slightly. I stopped them with my foot, but they start back up again on their own. I played with the shifter and still they spin. I tried stopping them again, but when I let them go they spin up again. I think there is a problem with the clutch. I'll tell my sister to go schedule an appointment with the dealer. That is unless, you guys thnk this is normal?

avenger

okay, here we go...


The wheels spinning are normal... everything is ok... see where the arrow points? when the wheels are up on the ground the ever ever so slight resistance in here will cause the shaft to barely spin.... if your sis revs it the wheels shouldnt react to a speed change, theres just baaaarely enough resistance to cause those wheels to spin


sorry bout the first post [IMG]i/expressions/face-icon-small-wink.gif[/IMG] and the pic is quick and dirty

Grey

iTrader: (61)

Kinda makes sense. Although I'de have to see a cross-section of the manual transmition when the car is in neutral to really get it. How can the drive shaft be just lightly engaged though? Seems funky. I know that automatic transmitions do this, but I don't know about manual transmitions? I don't think my car does this, just my sister's. I'll have to check to make sure. That is unless yours does that too?

avenger

in a transmission, your gears are engaged, see on that funky diagram? The black lines are the shafts. The Brown gears are solid on that bottom shaft. The green gears are on bearings spinning on that top shaft. The blue oval is connected solidly to the top shaft. When you shift, the "crappy gearshift" moves the oval onto the gear, where it locks in with the gear and makes a solid connection. The green things are synchros, they make your shift "smoove"

When you're on a lift, and there is no resistance at the wheels, the oil in the bearings makes just enough resistance that the shaft starts to barely move with the gear, instead of letting the gear spin on it.


For a better example of an MT :

click me!


Grey you going to any of the meets? I'll buy ya a cold one [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

edit: for clarity... the gears are always engaged, its the "oval" that moves and selects your "gear"

RockfordFosgateBwoy

its occurs due to resonance.

The cars engine operates with a natural frequency (vibration). since the entire car vibrates ever so slightly at the same frequency, the wheels gradually will pickup this same frequncy and begin to rotate slowly as well.
RF Bwoy

Grey

iTrader: (61)

I don't know about resonance? Maybe. The transmition explanation makes more sense now, although I still have to see if mine does this to be sure.



<< Grey you going to any of the meets? I'll buy ya a cold one [IMG]i/expressions/face-icon-small-smile.gif[/IMG] >>



Sure I am! Well, only one so far. We have another one coming up on Friday. I'll take that cold one, sure. [IMG]i/expressions/beer_yum.gif[/IMG]

avenger

<< its occurs due to resonance.

The cars engine operates with a natural frequency (vibration). since the entire car vibrates ever so slightly at the same frequency, the wheels gradually will pickup this same frequncy and begin to rotate slowly as well.
RF Bwoy >>



no, its resistance in the transmission. Your gears ride the output shaft on bearings, and when there is no resistance at the wheels the small amount of resistance in the bearings will get the output shaft spinning