1. Home
  2. Automotive Technologies
  3. Car rolling backwards while in 1st gear - what can happen?

Car rolling backwards while in 1st gear - what can happen?

Hi there,

I was visiting a friend and parked my car on a steep rising driveway. I left the car in the 1st gear (manual transmission).

Later I found the car at the lower end of the driveway. I moved it up again and witnessed how it started its slide in slow jerky motion while in 1st gear with weak parking brakes on. It was clear that the engine was engaged and pistons were moving. Yet the resistance was not sufficient to keep it there. I shifted to the reverse gear with the parking brakes on tighter and the car stopped moving.

Later I was backing of out of the driveway in the reverse gear and stopped while holding the clutch. Then I forgot that the gear was engaged and let the clutch go. The car jerked and died. A fraction of a second later I heard a 2nd clicking/jerking sound. When I restarted the car I heard the screeching noise for a few seconds, then it disappeared.

After that I drove home for ~150 miles. It was screeching occasionally. I made it home fine. At home I tried to locate to source of the sound and found that the alternator belt lost about 2/5 of its width (ignorance is bliss!). That is why it was screeching under loads.

Could the slow rolling backwards with the engine turning in reverse do something to the belt and make it partially brake when the car jerked? The distance driven between events was only a few yards. Should I expect few other "surprises" because of that?

Or are these things purely coincidental and the belt was weak and would have broken on another occasion?

Thanks!

Mike

Reply to
Mike Jackson
Loading thread data ...

I'd say it was purest coincidence. I'm thinking that dumping the clutch was probably the belt-killer, not the rolling backwards.

I can't see any realistic way for the engine turning backwards to cause any damage. Everything in there is still going to be turning in the same relationships to each other, just going the opposite direction from normal. About the only thing I can think of that *MIGHT* be damaged would be the oil pump, but even that seems highly unlikely.

I've had to park in similar situations many times, and in some of the cases, I've had the car roll backwards while in a forward gear. (or forward when in reverse) So far,I've seen no indication of trouble as a result.

Reply to
Don Bruder

I have heard that timing belts can become untensioned when the engine spins backwards, and jump teeth. That's why I've been told to depress the clutch when the car is about to spin. Don't know if that's true. Doesn't seem to be the issue in this case, though.

Reply to
Matthew Hunt

Sounds to me like an engine or tranny mount let go. This can allow the engine to move considerably under load. The movement could have allowed the belt to hit something peeling part of it off.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Mike Jacks>

Reply to
Mike Romain

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.