Autobox query

[television]

It was in "S" mode

It is said that some of those that do it in say S will not do it in W as W is a different gear ratio.

My drive is too steep for either to test, I will try it on a less steep road

 

[Dieselman]

It is said that some of those that do it in say S will not do it in W as W is a different gear ratio.

My drive is too steep for either to test, I will try it on a less steep road

There is a sprag clutch which comes into play in W mode but not S mode so no roll back is possible in W to allow better traction.

Roll back in S mode is down to the available torque transmited throught the 'verter at idle.

 

[television]

There is a sprag clutch which comes into play in W mode but not S mode so no roll back is possible in W to allow better traction.

Roll back in S mode is down to the available torque transmited throught the 'verter at idle.

Sorry mine rolls back and some others roll back in either mode , and it is down to the RPM in the end

 

[jaymanek]

The W S thing is definately true... when i drive cars back from auction I have to stop on a steep hill with lights on it.. if the car starts to roll back i simply flick the switch and all is fine.. this is true for most MB's...

 

[television]

The W S thing is definately true... when i drive cars back from auction I have to stop on a steep hill with lights on it.. if the car starts to roll back i simply flick the switch and all is fine.. this is true for most MB's...

Sorry Jay it is not true where I and some others live, the RPM is just 25 RPM too low Many cars will hold but not all, it depends on the engine RPM

 

[jaymanek]

Im sure the RPM does make a difference, but so does changing the switch setting... im talking in general not just for vlad's car..

 

[KLP 92]

if the car starts to roll back i simply flick the switch and all is fine.. this is true for most MB's...

I've noticed the same on various MBs mainly post 99.

 

[television]

Im sure the RPM does make a difference, but so does changing the switch setting... im talking in general not just for vlad's car..

We had a huge debate on the other forum, and I am not stupid regarding my own car,, it will not hold on my drive or roads around here in W

 

[jaymanek]

i think it varies from box to box.... but certainly all the normal W208/W210/W209/W211 etc all do this..

 

[television]

I have to come back to this is the facts ar more important.

I tried my car this morning especially to test it out again.

When cold my car rolled back in S and W as before a slight increase in RPM it held, but not with any form of sprag clutch.

I took the car for a fast run and returned, and reversed down my drive, now the car rolled in S and locked with a clutch in W, the same effect as a parking pawl.

I left the car for 3 hours and when starting again from cold the was no hold. went for a drive again and when I returned the W mode locked it up.

So is this part of the warming up the cat where the lower gears are held longer, for I only drove long enough to do that, once the lock up ceased, then the W lock works

 

[Vlad]

Malcolm...when you mention that your car rolls back, is it a gradual roll back or is it an uncontrolled roll back?

 

[television]

Malcolm...when you mention that your car rolls back, is it a gradual roll back or is it an uncontrolled roll back?

Its uncontrolled roll back unless the rpm is increased to make the torque C work