Transmission brake conundrum

[Bat21]

This thread got me thinking..... great idea and I'm sure it will do the job but...

Is it not just doing what the 'P' does in an auto... a mechanical means of locking the transmission? Obviously the X-Eng set up will be handbrake operated though.

What is the point of the 'P' position?

 

[adrianr]

H Paul

IIRC it drops a pin or has a pawl through that locks the output shaft of the transmission preventing movement.

 

[Chas]

Also, I don't think Mr MOT man will accept 'P' as a handbrake, so if the conversion works as well as expected it will get you through the MOT

 

[Bat21]

H Paul

IIRC it drops a pin or has a pawl through that locks the output shaft of the transmission preventing movement.

Yeah Aid I know what it does mechanically.... but what is the point?

Also, I don't think Mr MOT man will accept 'P' as a handbrake, so if the conversion works as well as expected it will get you through the MOT

I doubt he would either Chas, even though it does stop the wheels from moving... and more than the 18% efficiency required by the 'rule book' too

 

[adrianr]

LOL

thought you might!

 

[pugwash]

have you seen the size of the pawl?

it's a tiny piece of metal to hold back upwards of 7 tonnes when laden (admittedly its what i use, but on a hill when full i do feel more than a litte nervous). Have seen a parking brake on a classic range rover fail- it caused a fair bit of carnage before it stopped!

 

[Bat21]

have you seen the size of the pawl?

it's a tiny piece of metal to hold back upwards of 7 tonnes when laden (admittedly its what i use, but on a hill when full i do feel more than a litte nervous). Have seen a parking brake on a classic range rover fail- it caused a fair bit of carnage before it stopped!

I had one fail on a Volvo 264 V6 Auto, we were on a relatively flat car park at the time too luckily I was in the car at the time so the the result being only a rebuilt gearbox was needed.

I must admit I wouldn't rely on the 'P' in my LC on anything other than flat ground, so..... what is the point of the 'P' position? On my JDM import, I can't even take the keys out of the ignition until 'P' is selected.

 

[Rob]

Has Park always been on auto boxes or was it added at a later date? I'm not asking about Toyota gearboxes but auto boxes in general.

 

[jeepmadmike]

All the auto boxes I've ever played with have had a P

The one on my CJ 7 must be strong it will lock the back wheels at 70 and continue to function perfectly afterwards

I expect the P is there as a auto box has the issue of there being no mechanical connection from the engine to the axle unlike a manual box which can be left in gear and the engine used as a "brake"

I don't know how strong Yota P clutches are but landy ones brake with very little effort