Lurching after turning engine off????

[WestCoastSVX]

This seems strange to me, but I'm sure someone will know and it will probably be bad news.

The last couple days when I turn off the car, it suddenly lurches back an inch or so - enough that you really feel it sitting there in the car.

My usual procedure is to stop completely in a parking space, put the transmission into "P", let off the brake, put on parking brake, open my door (because the auto seat belt only works while the engine is on), then turn off the engine.

You can see from that order of events, that all brakes have been applied and released by the time I power down the engine and the car shouldn't (and never has before) move.

But now on that final step of turning off the engine, with the car in park and parking brake on, it "lurches" back a bit.

Very disturbing!

Transmission related?

[oab_au]

Troy this sounds like the Transfer clutch is binding. When you pull up the clutch is holding the drive line bound up, when you turn it off, the clutch releases, to settle the drive line.

Harvey

[TomsSVX]

Originally Posted by oab_au

Troy this sounds like the Transfer clutch is binding. When you pull up the clutch is holding the drive line bound up, when you turn it off, the clutch releases, to settle the drive line.

Harvey

+1.....................

Tom

[NiftySVX]

+2 hahahha

[Trevor]

Originally Posted by oab_au

Troy this sounds like the Transfer clutch is binding. When you pull up the clutch is holding the drive line bound up, when you turn it off, the clutch releases, to settle the drive line.

Harvey

It would appear that a retained forward torque loading delivered via the transmission, only becomes released when the ignition is turned off, at which point the car lurches backwards a little.

It is being suggested that the transfer clutch is holding retained torque against the rear wheel parking brake until this torque ceases when the engine is turned off, whereupon this available torque is applied to the front wheels.

However it is reported that at this point the transmission has been placed in park ready for the parking paul to engage. At which point the transmission should be running free and any retained engine torque should have been disconnected and released.

It would appear that engine torque must wrongly remain applied, when in park, until the engine is turned off. A control solenoid could be faulty and a diagnostic check is the obvious next step.

[TomsSVX]

Originally Posted by Trevor

It would appear that a retained forward torque loading delivered via the transmission, only becomes released when the ignition is turned off, at which point the car lurches backwards a little.

It is being suggested that the transfer clutch is holding retained torque against the rear wheel parking brake until this torque ceases when the engine is turned off, whereupon this available torque is applied to the front wheels.

However it is reported that at this point the transmission has been placed in park ready for the parking paul to engage. At which point the transmission should be running free and any retained engine torque should have been disconnected and released.

It would appear that engine torque must wrongly remain applied, when in park, until the engine is turned off. A control solenoid could be faulty and a diagnostic check is the obvious next step.

No Harvey hit the nail on the head... Constant fluid pressure is applied to the transfer clutch assembly... This w/ turning the vehicle causing an uneven rotation of front and rear wheels will cause torque to build in the driveline... Not until the engine is shut off and the oil pump ceases to create pressure is the clutch allowed to release.

Tom

[Trevor]

Originally Posted by TomsSVX

No Harvey hit the nail on the head... Constant fluid pressure is applied to the transfer clutch assembly... This w/ turning the vehicle causing an uneven rotation of front and rear wheels will cause torque to build in the driveline... Not until the engine is shut off and the oil pump ceases to create pressure is the clutch allowed to release.

Tom

Thanks Tom,

I understand what you are saying and in which case the problem would not show up if the vehicle has been driven for some distance in a straight line, immediately before being parked, e.g. run straight into a garage or driveway.

Trevor.

[WestCoastSVX]

Originally Posted by Trevor

Thanks Tom,

I understand what you are saying and in which case the problem would not show up if the vehicle has been driven for some distance in a straight line, immediately before being parked, e.g. run straight into a garage or driveway.

Trevor.

You hit it right there, Trevor. I have indeed not noticed it when pulling fully into my garage - about 20 feet straight total. Yet it does happen in parking spaces or stopping short of the garage in my driveway.

Thanks all of you for quick diagnosis and confirming each other.

Now to go search what exactly this means for my car and my wallet.

[SilverSpear]

Originally Posted by MacGyver

My usual procedure is to stop completely in a parking space, put the transmission into "P", let off the brake, put on parking brake, open my door (because the auto seat belt only works while the engine is on), then turn off the engine.

Not related to your case Troy, but I usually put the lever on "N", pull the handbrake, take my foot off the brake pedal, let the car settle on the handbrake, then put the lever into "P".

On flat surfaces, I leave the car on "N". I don't want anyone to hit me while parking and break my tranny along with my rear bumper (they nailed the latter tho ).

[TomsSVX]

Troy, you are having an intermittent fault. Probably a high resistance issue with the solenoid when it gets hot... The power light will only flash on the start-up AFTER the problem occurs

Tom

[WestCoastSVX]

Am I hurting anything by driving it around like this?

What is exactly happening when the solenoid fails? Does the AWD not work?

Main thing is I just don't want to make anything worse with the transmission. Not a matter of money right now, just finding time in the schedule to take it to a shop.


This wouldn't happen to be the cause of the strange brief buzzing noise I hear during low speed turns on occasion, could it? I've discussed in another thread over a year ago, even had the shop test drive it around, but no one could ever pin it down.

[Trevor]

Originally Posted by MacGyver

Am I hurting anything by driving it around like this?

What is exactly happening when the solenoid fails? Does the AWD not work?

Main thing is I just don't want to make anything worse with the transmission. Not a matter of money right now, just finding time in the schedule to take it to a shop.


This wouldn't happen to be the cause of the strange brief buzzing noise I hear during low speed turns on occasion, could it? I've discussed in another thread over a year ago, even had the shop test drive it around, but no one could ever pin it down.

Kia ora Troy,

In point of fact the AWD is probably working overtime.

Everything would indicate that your centre clutch is partly engaging when it should be free, which means unnecessary wear on the friction surfaces. The degree of harm will depend on the level of binding taking place.

The buzzing could very well confirm a faulty solenoid "C", i.e. it is not operating properly and the valve is sticking. This would represent good news, if it indicates that only the solenoid requires replacement.

[WestCoastSVX]

Originally Posted by Trevor

This would represent good news, if it indicates that only the solenoid requires replacement.

Thanks, Trevor, I certainly hope so!

Originally Posted by Trevor

In point of fact the AWD is probably working overtime.

Makes sense with what Tom was saying back at the beginning too. And when it does this, it does feel similar to how my truck does when locked into full 4 wheel drive.

Probably time to contact the shop and see how much $$$$.