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My RAV4 Committed Suicide - how and why

I lent my manual transmission 1998 RAV4 to a friend, who parked it in his sister’s driveway. After 12 hours parked in the driveway, the car rolled down the driveway, across the street, down another hill, and hit a wall, thereby becoming a total loss for insurance purposes. My friend swears the car was in first gear and the parking brake was on before and after the rollaway. The car actually didn’t look that bad, and the guy who towed it back up the hill actually drove it for a while and said it was fine (except for body damage). Judging by the hill, I would have expected a lot more damage, and the friend is, frankly, believable. Intuitively, you feel that something was slowing the car down.

Any theories? The car was routinely driven in San Francisco, and I was always really careful about curbing the wheels when parking, to the extent of letting the car coast into the curb to make sure the curb alone could hold the car. So, if something were wrong, I may not have noticed it, but that is unlikely. It also went to the dealer every 5000 miles and had its clutch replaced about 35,000 miles ago. I got 90,000 miles out of the first clutch. I used the parking brake occassionally to hold the car when starting out in first, but not often.

I sort of leaning towards driver error more than anything as the cause of this, but the 12 hour delay puzzles me. He said he was packing the car the shut the tailgate right before the accident.

Parking brakes can be weak, sometimes have to be pulled VERY hard, expecially to prevent a car from rolling backwards.

The thought had occured to me. If the hill is steep enough (and in SF there are a couple where you have to park perpidencular to the curb because of that) it is lucky if they hold at all. Still, there is the 12 hour delay.

Perhaps the brake wasn’t pulled that tightly and the tranny wasn’t securely in gear, and regular tremors in the earth vibrated them loose.

Or perhaps some kids were fooling with it.

Or as things cooled the brakes loosened slightly, the compression dropped, so it began to move. I don’t find the 12 hours that much of a puzzle.

The best parking brake, IMHO is a chock to put in front or behind a tire depending on the slope of the hill. In the old days of brake drums, the parking brakes were notorious for letting the car roll backward. The big jet aircraft I am certain have brakes on the wheels, but when the aircraft is parked, the wheels are always chocked. (I have no idea whether the pilot is instructed as to what gear to leave the jet engine in).

When I was a kid and most people had manual transmissions, more than once a car would back itself down the driveway and into the street. If I really want to depend on the parking brake, I put it on and then see if it holds before putting the car in park.

I am not aware of the shift pattern on that vehicle but with the compression loss from many miles, if mistakenly left in 5th gear the engine compression would offer little resistance.

Everyone makes mistakes. But, that the car did not look too bad would be proof to me that the parking brake was partially on and did not gather as much speed as it could have. IMO, if your friend was an experienced manual transmisionn owner, it’s very intuitive to leave it in gear. If it isn’t your car, it’s easy to leave it in the wrong gear, like third and not put the emergency on hard enough…once it starts, momentum builds on a hill. @texases explanation seems very reasonable too.

This AM my wife asks me why the Toyota Sequoia is about to go off the “cliff” at the edge of our driveway? Now the driveway is currently a sheet of ice, and the temp is just over 34 degrees at the time and apparently the SUV “slid” down the driveway about 50’ until it was stopped by a small pile of snow at the driveway’s edge. Surprised the “----” out of me, but no damage in this case.

Strange stuff happens. My guess in this case the parking brake was on enough to hold the car when the brakes were warm, but as they cooled the parking brake didn’t hold. With the car in gear the clutch can still slip (same thing when it is cold) and it seems the car slowly made it’s way down the hill. This is still driver error. The brake should have been on harder, and the steering wheel should have been turned so the car would not go straight back. With the key out of the ignition lock the steering wheel is held in position, so if it was turned the car would not go far.

In my driveway slip situation, that is driver error too. I put a chuck under a wheel and turned my steering wheel, and left it parked 4WD so it shouldn’t go anywhere tonight.

I think a car – if the parking brake wasn’t on tight or let loose for some reason – could still coast downhill in 1st gear if the hill was really steep. This wasn’t on that steep section of Filmore was it? I’ve had some interesting parking experiences on that hill myself … lol … Anyway, it would just coast more slowly in 1st gear than if it were in 2nd gear is all. And it may be that it wasn’t quite fully engaged in 1st gear, so when it started to coast, it went back to neutral. The person who discovered it, if they checked the gearshift position, would know one way or the other.

There’s always a slight possibility that the starter motor engaged too. If the selenoid contacts were very worn, they can sort of almost weld together, and this condition can cause the starter motor to engage mysteriously, and the car drive away, hours after the car is parked. A mechanic could inspect the starter motor contacts and easily prove or disprove this theory.

Dagosa - I’m leaning towards not putting the parking brake on enough, and somehow leaving the car out of gear. In any event, the insurance company was very nice about the whole thing and I was going to replace the car soon anyway.

The only other time I knew of when a car wouldn’t hold was a situation where the clutch was about to go out. I suppose if you put the car “in gear” while stopped, the gears wouldn’t mesh and it would be easy to start slipping.

Fillmore is one of the streets where parallel parking is now prohibited. You have to park at a 90 degree angle to the curb. I always laugh about Car & Driver reviewers who talk about the ‘driving experience.’ Try Fillmore Street, a 1968 manual transmission VW bug, and a 75 year old woman driving that hill (and talking non-stop) in stop and go traffic without letting that car slip back one inch. I was the passenger, but it was impressive.

Personally, Fillmore Street in light traffic wasn’t that bad with a manual transmission, but being fifth in line at the stop sign was never much fun.

The steepest hills are usually one-way downhill though.

Being in gear with a manual isn’t like ‘Park’, it’ll turn over given enough push and time.

I’d guess a weak park brake and stress on the tranmission internals causing it to pop out of gear.
Even an automatic transmission can pop out of PARK in the right situation.

While parking on a steep grade and as an additional measure, I’d recommend turning the wheels toward the curb so if something does give up the curb would (hopefully) stop the movement.

Wasn’t there a Car Talk puzzler a few months back that discussed this very same phenomenon? I seem to recall that there were similar solutions and discussion with Tom and Ray about how this may have happened. When I first started driving, I was told that when you are driving a manual transmission vehicle, you should always turn the front wheels when you parked, so that if the vehicle should start to move the tires would come up against the curb and stop the vehicle from rolling away, especially on a hill. Of course, if this was in someone’s driveway there probably isn’t a curb there, but turning the wheels would still have a similar effect as the car would go sideways and the momentum would be broken and the vehicle would come to a stop. I also agree with UncleTurbo, The brake pads may have loosened as they cooled thus reducing their hold over the 12 hour period. Inexperience has taught your friend a valuable lesson. The upside to this is if you were able to keep the RAV4 you may be able to repair it. My insurance company totaled out one of my cars because I rubbed a guard rail just enough to put a small crease in the fender and popped the passenger mirror off. I kept the car, replaced the damaged parts and continued to drive it.

IMHO, it does not have to be out of gear to roll, it just has to be in the wrong gear. Third is next to first and if it’s not your car, you could easily leave it in third, the parking brake could not have been on enough and as it cooled the car rolled but with some friction. Enough friction to be damaged less then you thought.
That’s my story and I’m sticking to in it. I leave several 4 by 4 s on the ground and line the perimeter with railroad ties as the edge falls down an embankment. I instruct my wife and visitors to back up against or turn wheels into them.
If I lived with a steep drive, I certainly would do the same…