Car moving while in neutral... other strangeness.

TridenT

Lifer
Sep 4, 2006
16,800
45
91
So, I have an automatic. I can't remember how long this has been happening, but anyway. If you rev the car to past like 6,000RPM while in neutral while moving the car will jerk forward a bit.

Anyway, jacked up the car today on 4 jack stands. Turned it on, put it in neutral. Wheels move. I was like, "Uh..." Press down the gas a little bit, wheels move faster... It's all very touchy, especially brakes. Press down on the brakes like I normally do and it jerks the car because it stops the wheels instantly. Gotta be gentleee

Anyway, I put it up there to test my cruise control. I wonder how it'll work out. It makes a weird clicking sound when I have cruise control on and I can only have cruise control on after 25mph... this will be fun. If I run through the house, I'll let you all know. I'm testing to see if I can fix the noise issue.
 

Bignate603

Lifer
Sep 5, 2000
13,897
1
0
Makes life easy. Doesn't have everything going towards the back end either.

Good luck with that, putting a car up with jackstands at all 4 corners is a great way to have the car fall. With the cruise control on this could end in the most epic Trident thread ever.
 

TridenT

Lifer
Sep 4, 2006
16,800
45
91
Why are you rev'ing the engine up to 6k while in neutral?

Boredom. It's not like I hold it there either though.

Anyway, got the car into 3rd gear. It's really difficult to test the cruise control noise this way. It's actually, like impossible... :( The problem is that when I set the cruise control for 30-35mph (lowest speed I can put it at really with this setup), it'll be like, "ahh, there's the clicking I hear..." and then it'll start to adjust the pedal manually and so it'll start to go down, the speed(because I take my foot off a bit) and then it presses down A LOT. So the car will go from 30mph to start screaming at 60mph and then it'll keep going if I didn't hit the brakes or turn it off. So I was like, "fuckkkk. no way to test this I guess?"

Sucks man. I'd have to have a person looking at the car engine bay while I test the stuff to see what causes the noise.
 

TridenT

Lifer
Sep 4, 2006
16,800
45
91
Apparently it's something closer to the engine throttle according to my source. I'm skeptical. It sounds like it's really close to the drivers side where as throttle is in middle of the car. :/
 

HarryLui

Golden Member
Aug 31, 2001
1,518
33
91
It's normal. There are bunch of fluid that is moving inside the torque converter and automatic transmission. Even though your car is in neutral, the force of the moving fluid can still turn the gear.
 

Bignate603

Lifer
Sep 5, 2000
13,897
1
0
Boredom. It's not like I hold it there either though.

Sounds like a great reason... ;) Why go looking for problems when there's no issues during normal driving? Cars are made to be driven like a sane person would drive them. If you start doing things that a normal person wouldn't do they'll do funny things.

Apparently it's something closer to the engine throttle according to my source. I'm skeptical. It sounds like it's really close to the drivers side where as throttle is in middle of the car. :/

My van has its cruise control unit on the driver side, far away from the throttle. It's connected by a cable over to the throttle.
 

exdeath

Lifer
Jan 29, 2004
13,679
10
81
Neutral releases all brakes and clutches allowing the gears to move freely without transferring power. It should not be moving in neural at all
 

TridenT

Lifer
Sep 4, 2006
16,800
45
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Sounds like a great reason... ;) Why go looking for problems when there's no issues during normal driving? Cars are made to be driven like a sane person would drive them. If you start doing things that a normal person wouldn't do they'll do funny things.



My van has its cruise control unit on the driver side, far away from the throttle. It's connected by a cable over to the throttle.

So does mine. The cruise control mechanism is on the drivers side and that's what I thought was making the noise, the actual unit. I still believe it is that, but my source says it's not. Idk.
 

MotF Bane

No Lifer
Dec 22, 2006
60,801
10
0
Good luck with that, putting a car up with jackstands at all 4 corners is a great way to have the car fall. With the cruise control on this could end in the most epic Trident thread ever.

"My car went through the house! It's not my fault though."
 

helpme

Diamond Member
Feb 6, 2000
3,090
0
0
Good luck with that, putting a car up with jackstands at all 4 corners is a great way to have the car fall. With the cruise control on this could end in the most epic Trident thread ever.

Wait, why is this a dangerous support method? I must have misunderstood? My cars have jack stand support points on the pinch welds at each corner. That's how I've fully supported my cars when I needed it competly off the ground.
 

dawp

Lifer
Jul 2, 2005
11,347
2,709
136
Wait, why is this a dangerous support method? I must have misunderstood? My cars have jack stand support points on the pinch welds at each corner. That's how I've fully supported my cars when I needed it competly off the ground.

it isn't just the fact that he's has jack stands at all 4 corners, it's that plus the fact he's reving the engine while in gear, which could cause the car to move and fall off the jack stands while in gear. it's pretty easy to knock a car down while supported like that. I would not start my car if it was supported like that.
 

helpme

Diamond Member
Feb 6, 2000
3,090
0
0
it isn't just the fact that he's has jack stands at all 4 corners, it's that plus the fact he's reving the engine while in gear, which could cause the car to move and fall off the jack stands while in gear. it's pretty easy to knock a car down while supported like that. I would not start my car if it was supported like that.

Ah, gotcha. I've had to star my car while it has been in the air to diagnose problems before. I tried to rock the car as hard as I could from the sides and ends to see if it felt stable. It seemed ok and didn't show any instability while it was starting... But yeah, I don't put it in gear and rev it. I can see how getting on an off the gas could cause serious problems.
 

jlee

Lifer
Sep 12, 2001
48,518
223
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it isn't just the fact that he's has jack stands at all 4 corners, it's that plus the fact he's reving the engine while in gear, which could cause the car to move and fall off the jack stands while in gear. it's pretty easy to knock a car down while supported like that. I would not start my car if it was supported like that.

Starting isn't typically an issue (that's the easy way to bleed an MR2's coolant system..jack up the tail and let it idle), but I could see spinning wheels possibly causing problems.
 

sdifox

No Lifer
Sep 30, 2005
98,822
17,302
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Starting isn't typically an issue (that's the easy way to bleed an MR2's coolant system..jack up the tail and let it idle), but I could see spinning wheels possibly causing problems.

You forgot the part where a person is standing in front of it leaning into the engine compartment...
 

TridenT

Lifer
Sep 4, 2006
16,800
45
91
it isn't just the fact that he's has jack stands at all 4 corners, it's that plus the fact he's reving the engine while in gear, which could cause the car to move and fall off the jack stands while in gear. it's pretty easy to knock a car down while supported like that. I would not start my car if it was supported like that.

Not really.

The car was pretty freaking solid on those stands. It wasn't going anywhere.
 

thescreensavers

Diamond Member
Aug 3, 2005
9,916
2
81
lol, I hope your not revving the engine just sitting there. I hope you have a fan blowing air over the radiator.
 

JCH13

Diamond Member
Sep 14, 2010
4,981
66
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The wheels are spinning because your automatic transmission is acting like a really shitty torque converter, transmission fluid is coupling all of the clutch plates together. I bet you could keep the wheels from spinning with your hand (please do not try though).

Undoubtedly doing 6k revs in neutral isn't great for your transmission, and running the car on cruise control while on jack-stands is just stupid. Any little mistake that would have been "damn, my car fell of the stands" will turn into "shitshitshitshit my car just took off through a wall and ran over someone."