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2021 Hybrid Corolla, jolt on changing from park to reverse


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Does anybody else experience a jolt moving from park to reverse?

It used to happen rarely, now it happens nearly every time.

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2 hours ago, camellia30 said:

Does anybody else experience a jolt moving from park to reverse?

It used to happen rarely, now it happens nearly every time.

Hi, usually this can happen when you park the car on uneven places and using no handbrake (parking brake)., or when foot brake not been pressed properly the car moves immediately after gear selection is made and jolts, the reason is that  the parking lock in your transmission goes into odd position, that’s all, not a mechanical issue but slightly annoying. To avoid all that happened you can try the following procedure: 

Park the car at the same place as usual, select N (neutral) pressing the brake pedal, apply parking brake and with the car in N depress brake pedal so the car can be hold entirely on its parking brake, select P on gear selector and  turn off the car. When you start next time and  select gear D or R from P there won’t be any jolts anymore. 👍 Done that on all types of automatic transmission cars including few Toyota hybrids models with success. 
Regards 

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I did that exact procedure for a while (and still do if I remember to do it) but know that it does not help. This is parking on the flat by the way.

I can tell when it is going to jolt as it is an effort to move the gear lever from P to R.

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The fact that it is an effort to move from park to R indicates that that the car is resting on the park mechanism ie the car has moved slightly before the parking brake has engaged.

I make sure I keep my foot on the brake pedal before engaging park then waiting for the parking brake to energise.

if you have done what tony had has suggested and you still have a problem suggest you have a word with dealer.

 

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Ok, sometimes even you had followed the procedure it is possible to get that jolt again, all because of the odd position of the parking lock, these transmissions has nothing else that can cause this behaviour., What I do when this happens to me, I just select D or R and let the car move a bit, 2 feet is enough, then do the procedure again if on uneven road or just put in park and leave it like that , the engine starts and stops few times afterwards while I am waiting inside and no jolts at all, but if I just leave it as it was before, every time ice start does jolts. Maybe try this too and see how it does yours. 
Regards 

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9 hours ago, camellia30 said:

I did that exact procedure for a while (and still do if I remember to do it) but know that it does not help. This is parking on the flat by the way.

I can tell when it is going to jolt as it is an effort to move the gear lever from P to R.

My Yaris is much the same

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My car does the same thing. I can't figure out why and when. It happens 1 out of 5 times, more or less "shaky". My own driveway is flat and level, I drive in very slowly, park the car, and still it happens. 

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The transmission brake parking pawl is driven by an electric motor on the Auris and Prius, the newer models don't have this, they have a Bowden cable arrangement

I'm just speculating here, the electric motor type could be designed to push and pull the pawl into and out of engagement, that would be very simple to design.

With the Bowden cable operation (like a bicycle brake cable, or handbrake cable) the gear selector cable will forcibly engage the pawl, but I presume its withdrawal is done by a spring, (it is not usual to have a Bowden cable used in a 'push and pull' fashion, but not unheard of). 

Depending on how tight the pawl is engaged, perhaps the spring is not immediately releasing the pawl, because depending on its exact engagement point, it is sometimes stiff to release?  The difference in 'feel' at the gear lever could be the lack of movement of the pawl engagement at the other end of that cable, and your moving the stick is then loading the mechanism to release, which it doesn't actually do until you try to move the car in reverse.

Also, the electric actuator will have no adjustment procedure - it just bolts to the side of the 'box, but there is surely one for the cable/mechanical one, which gives the opportunity for it to not be quite correctly adjusted at the factory, especially if this was not recognized as a potential 'problem' during manufacture.

Or, it may not be anything to do with this....

The motor-driven brake actuator is definitely made in Japan, it's written on it, the mechanical/cable equivalent could be locally made, in France even, but this shouldn't make any difference.   :lookaround:

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1 hour ago, Gerg said:

The transmission brake parking pawl is driven by an electric motor on the Auris and Prius, the newer models don't have this, they have a Bowden cable arrangement

I'm just speculating here, the electric motor type could be designed to push and pull the pawl into and out of engagement, that would be very simple to design.

With the Bowden cable operation (like a bicycle brake cable, or handbrake cable) the gear selector cable will forcibly engage the pawl, but I presume its withdrawal is done by a spring, (it is not usual to have a Bowden cable used in a 'push and pull' fashion, but not unheard of). 

Depending on how tight the pawl is engaged, perhaps the spring is not immediately releasing the pawl, because depending on its exact engagement point, it is sometimes stiff to release?  The difference in 'feel' at the gear lever could be the lack of movement of the pawl engagement at the other end of that cable, and your moving the stick is then loading the mechanism to release, which it doesn't actually do until you try to move the car in reverse.

Also, the electric actuator will have no adjustment procedure - it just bolts to the side of the 'box, but there is surely one for the cable/mechanical one, which gives the opportunity for it to not be quite correctly adjusted at the factory, especially if this was not recognized as a potential 'problem' during manufacture.

Or, it may not be anything to do with this....

The motor-driven brake actuator is definitely made in Japan, it's written on it, the mechanical/cable equivalent could be locally made, in France even, but this shouldn't make any difference.   :lookaround:

The jolt happens at the exact moment I manage to move the gear stick out of park. Is it possible the cable arrangement is the other way round? Spring to actuate, cable pull to release?

Another thing, when I research this people say P to D and P to R as if there is a difference. It's always P to R, in a Corolla at least (as there is no choice to pass thru R I mean).

 

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1 hour ago, camellia30 said:

The jolt happens at the exact moment I manage to move the gear stick out of park. Is it possible the cable arrangement is the other way round? Spring to actuate, cable pull to release?

Yes, I think that is entirely possible - from what you've just added, most probable!  Is it safer (if there was a mechanical failure somewhere) that you force the transmission brake on, or off, with the cable operation in tension, from a designer's viewpoint? That is what I was trying to guess.

 

1 hour ago, camellia30 said:

people say P to D and P to R as if there is a difference. It's always P to R

The gear lever on the Corolla looks much more conventional than the older style, perhaps to make the hybrid drivetrain more 'mainstream' from a controls point of view.  The older control, this one is from a late model Auris, is like this:-

Toyota-Auris-Hybrid-gear-lever.thumb.jpg.d880a63f13363747650b850c5f5b11f5.jpg

So the transmission brake is separate (marked with a 'P' - the right hand button).  This 'P' brake, for those who find pressing the button a chore, comes on automatically when you turn the 'engine' off,  and releases the moment you move the lever to D or R, which as you mention, you can't do with regards 'D'.  A valid point.  The control above, as you might imagine, is easily operated with one finger.

Just as background, when you engage 'R', there isn't an engagement of gears happening, the car is driven backwards with one of the electric motors.  With the Toyota HSD, the engine is always connected to the wheels, albeit through a planetary gear train.  This takes a while to get your head around, but perhaps you already knew?

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As Gerg has well explained, when engaged R or D actually what happens is to unlock this pin that holds the whole planetary gear set together and prevent the car of moving,  I think because Corolla has more conventional gear selector has nothing to do with the jolt, this jolt happens inside the transmission and is the same in any other Toyota hybrids, Prius all variants,, Auris , Yaris etc. Have you put the car into P while waiting on red lights in traffic, I do often and the car moves slightly forward, sometimes after moves forward then moves backwards, I am talking about very little movement but can be felt inside the car, pretty much same when the car jolt, I actually only tried once Corolla GR 2.0 and got the jolt on my first drive ., the car was parked on uneven place with the rear wheels halfway on a slope, therefore for me was normal occurrence. , I am sure there is nothing wrong with the cars that does it, as they all do. 👍

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On 5/10/2021 at 3:45 PM, TonyHSD said:

As Gerg has well explained, when engaged R or D actually what happens is to unlock this pin that holds the whole planetary gear set together and prevent the car of moving,  I think because Corolla has more conventional gear selector has nothing to do with the jolt, this jolt happens inside the transmission and is the same in any other Toyota hybrids, Prius all variants,, Auris , Yaris etc. Have you put the car into P while waiting on red lights in traffic, I do often and the car moves slightly forward, sometimes after moves forward then moves backwards, I am talking about very little movement but can be felt inside the car, pretty much same when the car jolt, I actually only tried once Corolla GR 2.0 and got the jolt on my first drive ., the car was parked on uneven place with the rear wheels halfway on a slope, therefore for me was normal occurrence. , I am sure there is nothing wrong with the cars that does it, as they all do. 👍

I have experienced the car moving forward slightly occasionally when I park. How is that possible with the handbrake on?

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2 minutes ago, camellia30 said:

I have experienced the car moving forward slightly occasionally when I park. How is that possible with the handbrake on?

Hi, 

I mean by “moving slightly” actually not moving at all but trying to., the whole car is trying to push itself forward, this is absolutely normal in all Toyota/Lexus hybrids and it’s something that can freak out many new owners. Btw when this happens the car automatically applies her main brakes on top of the hand brake if the second been engaged or disengaged , leaving the car in P only it’s ok . , no risk the car will drive away., Corolla has an auto handbrake too.  My car has manual hand brake and it’s shift by wire but the jolt is there too. You maybe just need some time to get use to it. 👍

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