Is it normal that the car rolls backwards in gear when parked??
05-24-2006, 08:58 PM
#1
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Is it normal that the car rolls backwards in gear when parked?? Hey guys, i noticed something, that i hope is normal, but i dont see how it can be. I parked my car and im sitting in it and its slightly on a uphill slant, i put the car in third and shut it off, about a min later, it starts to ever so slowly roll backwards. I put it in first and it doesnt move at all? is something wrong?
05-24-2006, 09:28 PM
#2
nothing wrong, you expect the the engine's compression to be strong enough to hold 3400 lbs of weight??
Nothing wrong with that, that's why you have a parking brake. In the event your parking brake failed, at least it will only roll slowly down and minimize any damage to it and whatever may be in its way...
Nothing wrong with that, that's why you have a parking brake. In the event your parking brake failed, at least it will only roll slowly down and minimize any damage to it and whatever may be in its way...
05-24-2006, 09:47 PM
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i just thought when you put the car in gear, it shouldnt roll back at all, kinda like when you put the automatic in park and dont use the ebrake? you know?
05-24-2006, 11:54 PM
#5
An automatic has a park option that locks the transmission preventing movement.
A manual car simply puts a direct connection from wheels to engine. There's no "lock". Just think, with a breaker bar and a socket, you can turn the engine by hand... Now picture the amount of force a car has when rolling down a hill? Ever push a car while in neutral? How about up a 2-3 degree incline...? The force you can exert is strong enough to turn an engine... now think of the force of the weight of the car being accelerated by gravity being applied to turn that same crankshaft you can with some effort turn by hand yourself...
The parking brake MUST always be used on manual cars.
A manual car simply puts a direct connection from wheels to engine. There's no "lock". Just think, with a breaker bar and a socket, you can turn the engine by hand... Now picture the amount of force a car has when rolling down a hill? Ever push a car while in neutral? How about up a 2-3 degree incline...? The force you can exert is strong enough to turn an engine... now think of the force of the weight of the car being accelerated by gravity being applied to turn that same crankshaft you can with some effort turn by hand yourself...
The parking brake MUST always be used on manual cars.
05-25-2006, 11:17 AM
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the gearing of 3rd makes it easier to turn the engine over than 1....kind of the same pronciple of why u roll start in second gear and not first...it takes more force to turn the engine over in first...so u use second which turns over easier...
just leave it in 1st and pull up the parking brake... voila! no more creeping
just leave it in 1st and pull up the parking brake... voila! no more creeping
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05-25-2006, 11:44 AM
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Think of first gear as a 1/4 drive ratchet trying to turn the crank, 3rd would be a 1/2 drive ratchet and 5th would be a breaker bar. The higher gear you put the tranny in, it multiplies the force on the crank. In low gear (1st) the force of gravity and the weight of the car don't have the power it takes to turn the crank. The car would be fine sitting on just about any incline in 1st gear without the E'brake. But some people like to set it for peace of mind.
05-28-2006, 09:52 AM
#11
depends on the incline you park on, if rolling forward, I'd put it in first.
If rolling backwards, I'd put it in in first. For most everyday parking, just get it in a gear and make sure the parking brake is on.
I don't like putting it in reverse too often due to the need to do the "crash through" feature of the reverse lockout solenoid. Sure I want the feature to be there when I need it, but I always feel like if I keep "forcing" it into reverse, one day when I need reverse to be locked out ie a 4-5 shift and I end up hitting reverse and grenading the transmission.
If rolling backwards, I'd put it in in first. For most everyday parking, just get it in a gear and make sure the parking brake is on.
I don't like putting it in reverse too often due to the need to do the "crash through" feature of the reverse lockout solenoid. Sure I want the feature to be there when I need it, but I always feel like if I keep "forcing" it into reverse, one day when I need reverse to be locked out ie a 4-5 shift and I end up hitting reverse and grenading the transmission.
06-01-2006, 12:41 PM
#12
This is normal. Pushing the car 80 inches (1 tire revolution) would turn the motor over 4.5 revolutions in third gear. Pushing the car in first gear would turn the motor over 9 times. You can see pushing in third would have twice the leverage on the motor.
You can think of it as an invers proportionality: The easier it is for the motor to push the car, the harder it is for the car to push the motor. This is why engine braking works better at lower gears.
You can think of it as an invers proportionality: The easier it is for the motor to push the car, the harder it is for the car to push the motor. This is why engine braking works better at lower gears.
