Ducati Monster Forum

Kitchen Sink => No Moto Content => Topic started by: redxblack on November 26, 2010, 11:15:17 AM

Title: manual transmission and rolling downhill
Post by: redxblack on November 26, 2010, 11:15:17 AM
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.
Title: Re: manual transmission and rolling downhill
Post by: lethe on November 26, 2010, 11:20:09 AM
I always use the parking brake in my Golf but it won't roll when left in gear though.  :P
Title: Re: manual transmission and rolling downhill
Post by: mitt on November 26, 2010, 11:22:56 AM
Doesn't sound right, but no FHE.  Are there any matrix forums to bounce it off?

mitt
Title: Re: manual transmission and rolling downhill
Post by: redxblack on November 26, 2010, 11:25:01 AM
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.
Title: Re: manual transmission and rolling downhill
Post by: MendoDave on November 26, 2010, 11:40:16 AM
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.
Title: Re: manual transmission and rolling downhill
Post by: derby on November 26, 2010, 11:50:38 AM
Quote from: redxblack on November 26, 2010, 11:15:17 AM
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.
Title: Re: manual transmission and rolling downhill
Post by: ducatiz on November 26, 2010, 11:52:17 AM
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.
Title: Re: manual transmission and rolling downhill
Post by: redxblack on November 26, 2010, 12:11:22 PM
Quote from: ducatiz on November 26, 2010, 11:52:17 AM

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.
Title: Re: manual transmission and rolling downhill
Post by: ducatiz on November 26, 2010, 12:16:07 PM
Quote from: redxblack on November 26, 2010, 12:11:22 PM
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.
Title: Re: manual transmission and rolling downhill
Post by: lethe on November 26, 2010, 01:03:34 PM
was the floormat properly installed?  [cheeky]
Title: Re: manual transmission and rolling downhill
Post by: stopintime on November 26, 2010, 01:19:37 PM
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?
Title: Re: manual transmission and rolling downhill
Post by: MendoDave on November 26, 2010, 01:44:08 PM
Quote from: stopintime on November 26, 2010, 01:19:37 PM
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)
Title: Re: manual transmission and rolling downhill
Post by: redxblack on November 26, 2010, 03:13:31 PM
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.  [thumbsup]
Title: Re: manual transmission and rolling downhill
Post by: 671M900 on November 26, 2010, 03:36:00 PM
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.
Title: Re: manual transmission and rolling downhill
Post by: 1KDS on November 26, 2010, 03:41:54 PM
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
Title: Re: manual transmission and rolling downhill
Post by: mitt on November 26, 2010, 03:49:20 PM
One more thing I thought of, see what your manual says for what gear to use.  I think some cars say to use reverse gear.

mitt
Title: Re: manual transmission and rolling downhill
Post by: Johnny OrganDonor on November 26, 2010, 04:44:16 PM
Quote from: mitt on November 26, 2010, 03:49:20 PM
One more thing I thought of, see what your manual says for what gear to use.  I think some cars say to use reverse gear.

mitt

It's probably just a matter of using the shorter gear of the two.  I've had e-brakes freeze up in cold weather - I tend not to use 'em in the winter.
Title: Re: manual transmission and rolling downhill
Post by: redxblack on November 26, 2010, 06:00:30 PM
I've asked my wife to shift in the opposite direction of the hill. She's used to leaving it in first on relatively flat ground.

I've driven the 6 spd and LOVED it. If this wasn't under warranty, I'd seriously consider modding this one with a 6 spd. Apparently, they bolt on cleanly.
Title: Re: manual transmission and rolling downhill
Post by: erkishhorde on November 26, 2010, 07:14:01 PM
Quote from: Johnny OrganDonor on November 26, 2010, 04:44:16 PM
It's probably just a matter of using the shorter gear of the two.  I've had e-brakes freeze up in cold weather - I tend not to use 'em in the winter.

Had to get a couple friends to help me push an old VW bug that had the parking brake rust overnight. The clunk of it breaking loose was disturbing.

On topic, nope, never had a car roll while in gear and off. Although, once in heavy rain my civic SLID SIDEWAYS about a foot toward a drainage way while I was stopped at a light. It was the first heavy rain of the season and all the oil coming up made me drift. Scary as heck.
Title: Re: manual transmission and rolling downhill
Post by: Raux on November 27, 2010, 04:21:17 AM
I always park with the car in gear opposite of the hill, wheels turned the correct way AND the parking brake on

better safe than sorry.
Title: Re: manual transmission and rolling downhill
Post by: badgalbetty on November 27, 2010, 05:18:23 AM
The hand brake is put on the car for a reason. Use it.  [thumbsup]
Weight has nothing to do with a vehicle moving or not. When I drove semi, if I did not apply the maxxis( slang for tractor and trailer air brakes) the truck would roll- anywhere. Apply the brake and if you are inclined to leave it in gear then do that as well.
Title: Re: manual transmission and rolling downhill
Post by: Bladecutter on November 27, 2010, 09:12:45 AM
First off, read the owners manual.
It might say to use first gear or reverse, as some cars recommend one over the other for parking.
They will all say to also use the parking brake.

The reason why the car is rolling is because the engine is a small displacement engine, with extremely low friction engine internals.

Once the car is on a grade of any form, the weight of the car is able to exert enough force to overcome all the friction created by the axles, transmission, and the engine piston rings on the cylinder walls. What's good for fuel economy is not good for holding a vehicle still on a grade.

BC.
Title: Re: manual transmission and rolling downhill
Post by: redxblack on November 27, 2010, 09:47:18 AM
Makes sense. More sense than the guy at the service dept saying "it's supposed to do that" after confirming what I thought was problematic seemed problematic to him as well.

non-problem solved I guess.
Title: Re: manual transmission and rolling downhill
Post by: Ratfink749 on November 27, 2010, 01:15:58 PM
Is the car all wheel drive?  I've been in some AWD GM cars that have this exact problem and its a result of the front and rear drivelines slipping inside of the transfer case. (because its viscous/clutch drive and not a 100% locked chain drive)  If this is the case, then YES it is normal and YES.. set the parking brake.  If its not AWD.. well then..  I'm stumped.
Title: Re: manual transmission and rolling downhill
Post by: redxblack on November 27, 2010, 01:45:57 PM
FWD, not AWD. Yeah, it's weird.
Title: Re: manual transmission and rolling downhill
Post by: the_Journeyman on November 29, 2010, 02:57:49 PM
I've never had this happen, so I have little to offer.  However, I have had a Honda Accord I-4 w/ 5-speed and no rolling regardless of gear, same with my '94 Cavalier, again, I-4 w/ 5-speed.  My V8 Dakota w/ 5-speed doesn't roll either.

I understand the parking brake + cold weather thing though.  Stuck brakes are an issue.

JM
Title: Re: manual transmission and rolling downhill
Post by: ducpainter on November 29, 2010, 03:32:42 PM
My Focus does the same thing. Has since brand new, so I don't think there's anything 'wrong' with the car.
Title: Re: manual transmission and rolling downhill
Post by: lethe on November 29, 2010, 05:14:59 PM
Quote from: humorless dp on November 29, 2010, 03:32:42 PM
My Focus does the same thing. Has since brand new, so I don't think there's anything 'wrong' with the car.
What's wrong with your car is the loose nut behind the wheel.
Title: Re: manual transmission and rolling downhill
Post by: Randimus Maximus on November 30, 2010, 07:41:51 AM
From page 130 in the Owners Manual:

"When parking, firmly apply the parking brake to avoid inadvertent creeping."
Title: Re: manual transmission and rolling downhill
Post by: lethe on November 30, 2010, 05:25:48 PM
Quote from: Randimus Maximus on November 30, 2010, 07:41:51 AM
From page 130 in the Owners Manual:

"When parking, firmly apply the parking brake to avoid inadvertent creeping."
so it's a creepy car you say?
Title: Re: manual transmission and rolling downhill
Post by: redxblack on November 30, 2010, 05:54:05 PM
like the FREE CANDY van?
Title: Re: manual transmission and rolling downhill
Post by: lethe on November 30, 2010, 06:00:56 PM
Quote from: redxblack on November 30, 2010, 05:54:05 PM
like the FREE CANDY van?
that's what he seems to be saying, not a ringing endorsement for his company's products  [cheeky]