Almost had a runaway Jeep

[gtrsnax]

This weekend, while parked on a slope, and Greg was touching the door :flip: , my Jeep was facing up the hill. I swear it was in 1st gear. It rolled back a tick or two, like it skipped a tooth in the gears, then stopped. Greg gave me a "WTF" look, it rolled back another tick or so, and then I hopped in real quick as it did a third time I think and I turned it on and parked it across the hill, not up/down it.
Now, in the slight possibility that it was in another gear, maybe 3rd or maybe reverse, would that explain it ANY more easily than if it was in first? Why did my Jeep tease me about running away down the hill and probably killing lots of people in its path?


MOVED K9: Thread contains darwin, which is only a theory

[BESRK]

When you put a vehicle in gear it's relying on engine compression/friction to keep the drivetrain from turning. If the hill is steep enough it can make the engine turn and the vehicle can creep. If I'm on the trail and I'm on a really steep hill and have to stop, I put one of my tires against a tree to keep the vehicle from moving. First gear is usually enough to keep a vehicle in place in your average driveway but anything steeper and you should use a good parking brake, chock a wheel or maybe put the vehicle in 4 wheel low to increase the leverage of the engine over the drivetrain.

[gtrsnax]

Thanx Eddie, that explains why it didnt budge on the trail, but did afterwards.
My e-brake is....non-cooperative, but I hope to replace it soon.

[hecull]

When you're in a higher gear, the mechanical advantage can overcome the compression of the engine. In a higher gear, it takes more wheel movement with less resistance to make a little turn in the engine with it's normal compression resistance, thus making the force required less. Although it's counter-intuitive, it's mechanically sound.
It's like the polar opposite of the fact you can't start from a stop in 5th, and also why you push-start a manual in 2nd or 3rd, not first.

If you were in first or reverse, it's probably clutch time. If you were in 3rd, I don't think you have a problem, other than remembering to put it in first, and fix your parking break. Eddie's also right, being in 4-low will also help keep it in place, as that will increase the energy needed at the wheel to overcome the engine compression resistance.
Kyle

[K9]

FYI... common to use 3rd to POP-START an engine