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Shifting at the dots under WOT

Started by raueda1, 29 June 2020, 07:42 PM

raueda1

My car has never shifted at the speedo dots under WOT.  The tranny/throttle rod now seems to be in the sweet spot for low speed and partial throttle shifting and general drivability.  Kick-down switch is also fine. 

That said, I've never gotten the car to upshift at the speedo dots.  Not even close, always 15-20 mph short, maybe more.  By my reckoning the dot is pretty close to redline.  I wouldn't want to press it that hard very often, but I'd like to know I could.   

So what governs the WOT upshift points?  It doesn't seem to be the control rod.  Maybe the vacuum modulator?  Something else?  AFAIK the transmission is tip top and I don't have any vacuum leaks.  What to play with? Any insights appreciated, cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

daantjie

Dave looking at the transmission manual the 1-2 upshift is at 79 km/h and the 2-3 upshift is at 144 km/h under full throttle.  I see the dots on the speedo do not correspond with these numbers so not really sure which one is "right" ???
Daniel
1977 450 SEL 6.9 - Astralsilber

ptashek

Your car will never shift at the dots for a simple reason - they're not indicating shift points.
They indicate the maximum speed you should drive at in a given gear when shifting manually (using S/L/D positions).
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

revilla

Correct.
The dots (orange bars) are used for example when using the transmission lever in assisting breaking (down-shifting 4-3 or 3-2).  If you are in 'D' on 4th gear and you go to 'S' to force 3rd at a speed above the dots you'll basically force the engine into red zone revs. Not good.
Cheers

raueda1

Thank you gentlemen, this is actually great news.  No idea where I got the idea that the dots were WOT shift points, but the notion was stubbornly fixed in my brain.  So all was well all along. Nothing beats solving a problem by learning that it isn't really a problem!
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

UTn_boy

And remember that the modulator valve ONLY controls how soft or hard the transmission shifts. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

raueda1

Quote from: UTn_boy on 30 June 2020, 11:20 AM
And remember that the modulator valve ONLY controls how soft or hard the transmission shifts.
Great!  Another problem solved without ever leaving the couch.  Must be a first. Cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Randys01

I have observed over the years the red line on 6.9 variants sits between 5 and 5 and a quarter. I am yet to determine a pattern to this but I bet the max rpm per gear tabs on the speedo are not varied accordingly!! :-\

s class

The 5000 or 5250 redline on 6.9s is an early / late thing as far as I know. 


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL