So I have finally managed to get my grubby mitts on it...

[tode]

The jolt on 7g car is to do with the missing sprag clutches which assist with smoothing out downshifts, whilst software soothes the pain, it doesn't completely solve the issue that a rigerously engineered automatic transmssion wouldn't have.

I hope when 9g Merc transmission comes out, it has sprag clutches, then it will be smooth and lovely.

If I knew what a sprag was, I could comment. .

 

[television]

If I knew what a sprag was, I could comment. .

A sprag clutch is a one way clutch that turns an object in one direction and free wheels in the other

 

[tode]

A sprag clutch is a one way clutch that turns an object in one direction and free wheels in the other

Thanks. Don't really see why you need one, but I'll take your word for it.

(I looked it up in my English/French dictionnary, which told me sprag = "bean".

 

[television]

On the old 5 speed box it had one in the final drive, when you selected W on the box the car would not roll back on a hill, there is no room for one in the 7g box

 

[tode]

Well, there's no problem with roll-back, anyway. Even on a steep incline.

 

[television]

Well, there's no problem with roll-back, anyway. Even on a steep incline.

Yes I agree, to some extent it is to do with the engine idle speed, and certainly no problem even on my steep driveway

 

[LTD]

On the old 5 speed box it had one in the final drive, when you selected W on the box the car would not roll back on a hill, there is no room for one in the 7g box

Similar happens in the 5 speed box used in my W220.

In S mode it will roll (1st gear selected as base gear)
In C mode it will hold (2nd gear selected as base gear)

 

[television]

Similar happens in the 5 speed box used in my W220.

In S mode it will roll (1st gear selected as base gear)
In C mode it will hold (2nd gear selected as base gear)

Yes a very nice feature to have, but now we have the adaptive braking system, with this you can push the foot brake twice and the brakes lock on, when its time to take off, just use the throttle and the brake releases.

 

[gilbert121262]

Its an old mans car though

Thanks!!!

 

[Naraic]

If I knew what a sprag was, I could comment. .

http://en.wikipedia.org/wiki/Sprag_clutch

 

[LTD]

Yes a very nice feature to have, but now we have the adaptive braking system, with this you can push the foot brake twice and the brakes lock on, when its time to take off, just use the throttle and the brake releases.

NIce advance but what length of time would pads need to be contact on a very hot brake disc before it becomes detrimental to either fluid or disc ?

 

[television]

NIce advance but what length of time would pads need to be contact on a very hot brake disc before it becomes detrimental to either fluid or disc ?

You have a very good point there but to be truthful one only use this feature in traffic, so in reality this rarely happens, but it could as you say and I will bare that in mind when using it. thanks

 

[tode]

Similar happens in the 5 speed box used in my W220.

In S mode it will roll (1st gear selected as base gear)
In C mode it will hold (2nd gear selected as base gear)

Funny, I've never noticed that. I'll give it a try tomorrow.

 

[LTD]

Funny, I've never noticed that. I'll give it a try tomorrow.

I have a 5 speed box. You might have the 7 speed if it is a W221

 

[tode]

Yes, that's right.

 

[television]

Yes, that's right.

So no sprag in yours or mine

 

[Peter De La Mare]

I've now experienced 12 different 7g or 7g+ boxes and not one of them has delivered a lumpy shift from 2nd to 1st or rolled back on an incline.

It must all be in the mind Steve, or you have a neurosis about it or something :lol:

 

[television]

I've now experienced 12 different 7g or 7g+ boxes and not one of them has delivered a lumpy shift from 2nd to 1st or rolled back on an incline.

It must all be in the mind Steve, or you have a neurosis about it or something :lol:

I think that you are right and I will decline the offer to let him drive it

 

[tode]

So no sprag in yours or mine

WOT ! NO BEANS ! . . . (sorry)

While hunting for info about these sprag-thingies, I came across this by some MB whizz-kids. 7Gtronic plus

Seems they've brought out a new oil for the 7G plus: ATF134FE ?

 

[television]

That is a neat PDF thanks, yes there is new fluid and it can be used on all the older boxes, even the 5 speed, I do not have the plus version, one day