Rolling backwards in Drive (Auto box)

[Trickythemerc]

The seven speed box has no spragg clutches so it will roll back in drive.

 

[ray_hennig]

My old 300CE 5 speed auto has always held the thing, even on pretty aggressive slopes.

R

 

[John]

I can't 100% remember but I was pretty sure the 5g in my old 2004 E55 didn't roll back but both my subsequent 7g+ boxes do roll back (unless I initiated hill start assist or hold).

Does the 5g have these "sprag clutches" do you know @Trickythemerc ?

Sbc braking system or not? | Wheels, Tyres, Brakes & Suspension

 

[Trickythemerc]

Yes the 5g box will have spragg clutches. When MB designed the 7 speed box it was supposed to fit in the 5g housing, but all the components would not fit. To get round the issue they left the spragg clutches out to make things fit in the 5g housing, early 7g boxes were utter rubbish with clutch pack wear problems. The big V8's used to eat 7g boxes for fun, A redesigned housing would have been too big to fit into the tunnel of the then current chassis range and changing the chassis design would have meant applying for type approval again which they were never going to do on run out models.

One of my avoids when looking for My CLK was the 7 speed box, my 5g had a service at 70k with an extra fluid change at 110k and is faultless with lovely pink fluid.