As nash said, when MG1 is spun to crank the ICE, there will also be a counter-torque that is felt at the wheels. I believe that Toyota applies a momentary cancelling torque to MG2 to approximately nullify this reaction from the cranking of the ICE. This procedure usually works very well, but on rare occasions I have felt a small jerk when the engine cranks. When this happens, the car's motion is very minor.

Stan

 

Ehhh ... I'm not going to lose sleep over this. The car is never parked THAT close to anything anyway. This is my wife's car ... so I'll just tell her to keep an eye out for it.

 

What keeps the car from rolling downhill when the engine is off and the "transmission" is in park?

 

There is a pawl that engages a gear in the transaxle. This works just like in any automatic transmission.

This is also what keeps the car from rolling when the ICE starts! (per the original topic)

Unfortunately most parking pawls have some "lash" in them. This is why the car can roll a couple inches when in park. I wish they would use a friction brake instead. This would eliminate any movement.

 

Hence why we should all use our parking brake....at least when on hills. (I am just as much a slacker on that as many.)

 

Thanks for all the responses guys (and gals if any). I figured it was normal but just wanted to confirm since sometimes is a little more violent than others.

 

Agreed. But foot actuated parking brakes are a PITA. So I only use them when parking on a steep incline.

If the car has a hand brake I use it all the time. Instinctively.

I have actually thought about retrofitting the SE hand brake assembly and center console...

 

I agree with that! I probably would not go through the pain of a retrofit though.

 

I just noticed this today with a 2009 TCH with 500 miles. Very weird. Afer driving for 15 minutes or so (warm weather), I parked. Car in Park, parking break set. Keeps making a lurching/rocking, like the engine is cutting in and out.

It's as if I had the car in drive, foot on the brake, and giving it some gas. But my feet are off the pedals, the car is in Park, and the parking break is on.

Seems like a bug to me.

I also had my first "crash" with the TCH. (as in the car dying and shutting off). Later the same day, I drove 1 block from my home. I stop at a stop sign. A bunch of idiots lights come on. (Check engine, VSC, brake, a few others.) "Ready" light is on, but car won't move.

I'm glad I was on a quiet street; if could've been an issue in traffic. (Kinda scary for it to go t-i-t-s up on me.).

I did a power cycle off/on, and it came back like nothing happened.

 

Dying is not good. Yikes. I haven't had that.....luckily.

I do get the same of rocking when in park sometimes. It does feel like the ICE is running rough. The funny thing is, it has gotten a little warmer and I have not had it lurch as violently when the ICE first starts after "booting up" the car.