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is the 3 speed auto really a 4 speed?

Started by hokman, 01 September 2005, 12:04 AM

hokman

I found this post in mercedes in the movies.
http://www.hampstead.com.au/mb/Reviews-Movie_ID-276.html
Unbeknown to most the W116 DOES have a 4 speed box - 1st is (almost always) inoperative such that they run on 2nd 3rd and 4th . I had my 6.9 twigged so it had 1st. on kickdown @ 5kph. I sold it after a dodo in a 535 tried to hose me off - and my monster scare soon thereafter. Having blown his doors off I let him pass but 1k down the road he was at another red light on a 4 lane T junction waiting to turn left - which was also where I was heading . I rolled up to the lights in the outside lane and as I got there they changed green. Guess what? I tramped my Brown Beast. Well...it dropped into 1st, the half shafts thumped, the front lifted, the revs went to 4,000, the car went sideways, blue smoke + bits of chomped out bitumen and rubber (225x14 Michelins) flew up like a rooster tail as I had to throw on a near full opposite lock to keep it on line through the left hander as the roaring and bashing blasted me out through the corner and 3/4 sideways up the road. Within 3 seconds I was 150 metres away - coming out sideways into just about a line ball straight set up. A glance in the mirror showed the 535 still back down near the corner on the other side of the huge ball of blue (rubber) smoke and bits of torn up bitumen chips. The bloody beast frightened the you-know-what out of me so I sold it soon after. I'm now on my sixth Benz (my 6.9 was my second) but nothing came close to the sheer monstrous aggression of that 6.9 in (REAL) 1st gear. I've run a dino Ferrari - which was a superb orchestration @ 7,000 RPM of sheer joy (140mph) plus mucked about with a Harley for 35,000 klms - but neither came close to the subliminal maniacal monstrosity of that 6.9 when (innocently) unleashed - how DID the Germans lose the war given that they can put gear like that together?

This somewhat makes sense because if the auto box starts from second gear in normal acceleration, it wouldn't make sense if it only got one gear to change up.

AMG69

A four speed box??? OK, I'm intrigued.  I've never heard this before!
sigh....sitting back contemplating the next purchase..!

cth350

nope.  The early M100 and the M116 had 4-speed boxes.  All the M117's, and late <M100's & M116's after something like 1974 had the 3-speed box.  

The transmissions have completely different construction internally.  

The 4-speeds are rigged up so that under most circumstances, the transmission starts in 2nd gear.  Techniques to get a first gear start are published elsewhere. -CTH

AMG69

CTH, do you mean the 300SEL 6.3 had a four speed but ALL 6.9's had a three speed auto - thats how I always understood it.  What about the 600's (Grosser)....they were built from 1963-1980 so did they retain the 300SEL 6.3's 4 speed auto until they ceased production or did they swap to a three speed in the mid seventies?
sigh....sitting back contemplating the next purchase..!

hokman

If the first gear is so rarely used, then that means the 6.9 will have only 2 gears most of the time?!

The three speed auto is much smoother than the old 4 speed that doesn't have torque converter.

twn75

The three speed of the 70's is a very well constructed transmission. They are smooth without being slippery and are tight without being rough. However the old fashioned fluid coupling four speed does have more ratios which helps in acceleration and consumption especially on the NA models. I beleive some 3.5s had 4 speed manuals

As for the second gear start, I'm sure that there is some methodical convoluted reason that MB to this day does that I thought that it could have been designed for slippery climates but anyone that cannot modulate the throtle to keep the car from slipping should be riding a bicycle(There is a winter and sport mode switch on the shifter starting with the second gen W124 i think)My 1997 E420 has the switch and i think that it is a "load of crap" It makes it into a 300SD when accelerating from a stop which isn't why I bought the car

twn75

The three speed of the 70's is a very well constructed transmission. They are smooth without being slippery and are tight without being rough. However the old fashioned fluid coupling four speed does have more ratios which helps in acceleration and consumption especially on the NA models. I beleive some 3.5s had 4 speed manuals

As for the second gear start, I'm sure that there is some methodical convoluted reason that MB to this day does that I thought that it could have been designed for slippery climates but anyone that cannot modulate the throtle to keep the car from slipping should be riding a bicycle(There is a winter and sport mode switch on the shifter starting with the second gen W124 i think)My 1997 E420 has the switch and i think that it is a "load of crap" It makes it into a 300SD when accelerating from a stop which isn't why I bought the car

john skene

The 450 116 series 4.5 litre and the 6.9 litre transmission is not 4 speed, it is, and only ever was, 3 speed.

hokman

Oh, so the first gear in the 6.9 is that tall it can get to 100km/h?  That's why the 0-60mph figure isn't so fast.  styria, do you know the maximum speed of second gear?

Does the 4 speeds have a lower first gear?  The 6.3 has faster acceleration.

So the 4 speed uses fluid coupling, and the 3 speed uses torque converter, which one is better?

Mforcer

The top speed in each gear is indicated on the speedometer with the top speed of the first gear change marked by a small orange line and the top speed of the second gear change marked by two small orange lines.
Michael
1977 450SE [Brilliant Red]
2006 B200

john skene

Ok, these are the specs I have from British road tests. Weather has an effect on any results.                .

The 6.3 had a 4 speed box with a low loss fluid coupling, capable of roughly 53, 85, 132 and 216 K/Hr (5410 RPM) through the gears using a 2.65:1 rear axel ratio.
0 to 100 mph took roughly 19.7 seconds.

The 6.9 had a 3 speed box with torque converter, capable of roughly 105, 166, and 225 K/Hr (5200 RPM) through the gears using the 2.65:1 rear axel ratio.
0 to 100 mph took roughly 19.5 seconds.This with the dirty motor. The US spec motor took roughly 22.5 seconds.

hokman

The second gear can reach nearly 170km/h, I don't think any other car has a second gear that can go that fast.  I think the acceleration from the 105km/h (end of first gear) to the 170km/h (end of second gear) would be quite frightening, isn't it?

Unfortunately that old man doesn't want to drop the price, maybe he'll in the future, but now I've to find another car.  No one will buy that car anyways.

john skene

Sorry everyone, I made a mistake in the rear axel ratio for the 6.3.  It should read 2.85:1, not the 2.65 I listed.