[s_pphilip]

Originally Posted by KiloAlpha

Yes, it is perfectly normal for the car to move forward in jerks.

Thanks KiloAlpha, I never knew this, its an eye opener, I had this firm belief installed in me over years of never having witnessed a similar issue, parking lighter Maruti's, and over time it turned to blind faith, moreover this one time I believe the parking brake was not fully engaged and over time the car rolled down.

I always thought that reverse gear mechanism will stop the car from rolling forwards as it is against its normal movement, so in such instances what happens, is the load on the gear mechanism or the clutch?

People normally advice that you must always support the parking brake by engaging the opposite gear, i.e. in case the car faces downwards, slip into reverse and vice-versa.

[KiloAlpha]

Originally Posted by s_pphilip

Thanks KiloAlpha, I never knew this, its an eye opener, I had this firm belief installed in me over years of never having witnessed a similar issue, parking lighter Maruti's, and over time it turned to blind faith, moreover this one time I believe the parking brake was not fully engaged and over time the car rolled down.

I always thought that reverse gear mechanism will stop the car from rolling forwards as it is against its normal movement, so in such instances what happens, is the load on the gear mechanism or the clutch?

People normally advice that you must always support the parking brake by engaging the opposite gear, i.e. in case the car faces downwards, slip into reverse and vice-versa.

I live in a locality which has plenty of fairly steep slopes. This is what I always do when I park my car on the street.

Car facing downhill: Stop parallel to, and about 6 inches away from the kerb. Turn the wheel towards the kerb (so if I am on the left side of the road, turn the steering to the left). Then let the car gently roll down until the wheel is jammed against the kerb and car cannot move any more. Then engage reverse, pull up the handbrake real tight.
Car facing uphill: Same as above, only difference is I turn the wheel away from the kerb and engage 1st gear.

If no kerb, and slope is not too steep, then first turn the steering in the direction mentioned above and engage handbrake tight. The car should not roll down if you let go of the foot brake. Then engage 1st/reverse. If slope too steep, then either find a suitable stone or go park somewhere else

Always try to ensure that the load of the car is being taken up by a physical restraint (kerb/stone), or the brake. It should not be the drivetrain.

In your case, with a slightly old/weak clutch, it is likely that the clutch slipped. If the clutch is in good shape, then the external forces (car's weight) will try and turn the engine against the compressive forces in the cylinder. If the crank turns, it could result in your timing belt slipping a tooth. Not a good idea.
While the engine will not run in "backward" direction of rotation*, there is nothing mechanically preventing it from doing so if the crankshaft is rotated by an external force.

* not always true. It is possible to start a primitive 2-stroke engine and run it in the opposite direction. I have done it in the Rajdoot "doodhwala" 175. If you kick it just right, so the piston bounces back from just before TDC and the mixture ignites, then you can put the bike in 1st gear and go backwards.

MODS: please move this conversation to the appropriate thread in the technical stuff section? I think it belongs better there. Thanks.

[s_pphilip]

Originally Posted by KiloAlpha

If the clutch is in good shape, then the external forces (car's weight) will try and turn the engine against the compressive forces in the cylinder. If the crank turns, it could result in your timing belt slipping a tooth. Not a good idea.
While the engine will not run in "backward" direction of rotation*, there is nothing mechanically preventing it from doing so if the crankshaft is rotated by an external force.

I hope there is no significant damage that will be done, anything I need to proactively check as it is a crdi? Its worrisome.
I foolishly checked on multiple gradients to confirm.
Now that I am aware thanks to you, I will be double cautious and prevent this, thanks again.