manual transmission and rolling downhill

[redxblack]

So my wife bought a 2007 Toyota Matrix XR (certified used) a couple weeks ago. She will only drive a manual transmission car, because she likes driving while she drives. Anyway, unlike the other half a dozen cars she's ever owned, this matrix rolls when in gear on an incline if the brake is not applied. All her other cars stayed put in first gear. The incline it is rolling on is a slight grade for a parking lot storm sewer drain, not a real hill. I took it in to a reputable Toyota dealer who replicated the problem, took it to the techs and they said it works as designed - use the park brake. I got it in writing that this roll is "normal operation," and to use the park brake. I've never heard of such a thing. We've never owned a car with any kind of warranty, and paid a premium to get the certified car because we are getting too old to have to work around issues. I was wondering if any of you have had similar situations or if she should just get used to pulling the park brake.

[lethe]

I always use the parking brake in my Golf but it won't roll when left in gear though.  

[mitt]

Doesn't sound right, but no FHE.  Are there any matrix forums to bounce it off?

mitt

[redxblack]

I found a couple and will bounce there as well, but the first impression is they're more concerned with neon and fart cannon exhausts over there. I trust the motorheads here. Thanks everyone in advance for your help.

[MendoDave]

Well it sounds strange but the parking brake should be used anyway weather it's in gear or not. Not using the brake is a problem I'm trying to correct myself, its extra insurance against rolling away.
I wold start with a clarification from the techs as to why this design allows it to roll when in gear. You would be surprised at the amount of info you can get from these guys just by asking questions. Go back and be a pest.

[derby]

I got it in writing that this roll is "normal operation," and to use the park brake. I've never heard of such a thing.

the only thing keeping an in-gear manual car from moving in that situation is compression in the motor. i've had a car do that before (on a decently steep hill). no way in a million years would i park my car like that and walk away from it.

fwiw, this is why you're taught to use the parking brake AND curb your wheels on an incline.

[ducatiz]

The only reason having it in gear will stop the car is engine inertia.  If a car is on an incline, it will still roll without the parking brake.

It might be that the car has a funky flywheel arrangement OR that the engine itself doens't weigh enough versus the car weight to hold it in place.

Use the parking brake.

[redxblack]

OR that the engine itself doens't weigh enough versus the car weight to hold it in place.

This is what I am thinking, too. The "incline" it rolled on is so slight that it never seemed like an incline before. It's a very slight slope for water drainage, but seems pretty flat. I was surprised to see it roll to the sidewalk.

anything steep always gets the parking break, always. I can push this car while it is in first gear and move it. I've never had a car that could do that.

[ducatiz]

This is what I am thinking, too. The "incline" it rolled on is so slight that it never seemed like an incline before. It's a very slight slope for water drainage, but seems pretty flat. I was surprised to see it roll to the sidewalk.

anything steep always gets the parking break, always. I can push this car while it is in first gear and move it. I've never had a car that could do that.

engines are getting smaller and lighter, i think the new toyotas have papier-mache pistons.

[lethe]

was the floormat properly installed? 

[stopintime]

If the compression is what stops a car, and I think it is, a normal weight car with a small engine might be in trouble.
Another thought about new vs older cars - different firing order, overlapping valve opening? Am I thinking correctly here?

[MendoDave]

If the compression is what stops a car, and I think it is, a normal weight car with a small engine might be in trouble.
Another thought about new vs older cars - different firing order, overlapping valve opening? Am I thinking correctly here?

Firing order should have nothing to do with it. Its all about engine compression and the amount of mechanical leverage the wheels have over the engine. The wheels will have the least amount of mechanical advantage in reverse or first, and the most in overdrive. The engine should hold the car on a slight drainage slope in first or reverse, unless your car has some sort of compression release to help with a small starter, or a new fangled clutch design that requires the engine to be on in order to engage. You should try rolling it down a hill and see if the engine is even turning over. (air coming out of the exhaust is safer than looking at the engine drive belts. And of course have some help)

[redxblack]

Thanks again for all the replies - this is some good reading. I'll take it to a hill and see if I can get it turning over. I know just the hill even. 

[671M900]

I have a matrix xrs, different engine and transmission than the xr though (high compression and 6speed) but she doesn't roll in gear with the engine off. Are you putting it in gear opposite the downgrade?

Personally I park with both parking brake and in gear.

[1KDS]

I had a 6 cylinder F-250 with bad rings in two cylinders and it still stayed put, that yoter must have 4:1 compression