Thermo Valve?
 

Brothers of The Benz.
I've had my old sled for 14yrs. and it too is a slow shifter when cool/cold and a solid shifter all the time. Not smooth as silk but solid like a rock. When He shifts you can always feel it positive solid no slipping between gears.
Isn't it strange that when orderring a complete set of service manuals that a transmission manual isn't part of the set?
Is the transmission included on the new CD?
I don't use synthetic fluid, but as I've said as part of my maintaince program is to pump the sump empty and refill with MerconIII with ever engine motor oil change. Except for the intial pan removal when He was a Baby, and that was to remove any residual stuff from manufacturing, the pan and filter have never been serviced. Who knows, the filter may be almost stopped up?
The three fresh qts of fluid seems to give him a cool drink, so to speak.
Anyway what ever The Spiderman is doing appears to work.
Fresh fluid either all at once or a little at atime is what these rascal need!
Happy Trails Beep Beep from Donald The Spiderman in Houston!!!

Transmission is not covered in the W126 CD manual. Not even r&r.

Sixto
91 300SE
81 300SD

Sixto,
My car starts in 1st gear. The delay is in 2nd gear always. Since older MB transmissions started in 2nd gear, I think that is why it is commonly believed that it is holding 1st gear.

dlswnfrd is a man of men!
 

"I don't use synthetic fluid, but as I've said as part of my maintaince program is to pump the sump empty and refill with MerconIII with ever engine motor oil change."

Trans fluid every oil change, I'll bet that you could eat off of the inside of that trans! And silly me thought that changing the fluid & filter every 30K was aggressive...

Lunchroom
 

Brother of The Benz, kowached.
You've been peaking, how did you know where I ate my lunch, nowhere except the lower lunchroom!!!
And the Blue Plate Special only costs $2.98.
Happy Trails Beep Beep from The Spiderman in Houston!!!

How is the shift delayed? Is there a temp sensor, or is it oil viscosity?

My '79 300D took longer to shift into 3rd when it was cold. I would run up the rpms and back off to get it to shift earlier. It only started doing this after about 250,000 miles.

I seem to remember a thread (can't find it, though) describing an easy way to disable/defeat this cold shift delay. From what I understand, it is ONLY for an emissions reason, and disabling it would be of no detriment to the engine/tranny.

Ideas?

Thanks,

Thanks for a timely post. When I was driving up from the shore today, I thought I needed to take a look at why My 1990 300 SL seemed to delay making that first shift in the morning, but always ran perfectly after that. I had the filter replaced and fluid changed at the 30,000 mile service and now have about 48,500 miles. When I think back, it doesn't exhibit the delayed shift all of the time, but when it does, it's usually after sitting all night when the temperature is cool.

Bob

Slow or delayed shift 2 to 3
 

My 1990 300SL does the same thing too...only difference is that it does it EVERY time I switch off the ignition for more than 5 seconds, whether the car is warm cold or just been driven for 2 hours.

It does this whether ambient temp is 90 in summer or 30 in winter...only that now in winter, it is even more exagerated, taking much longer to change first time.

Once it gets going after the first shift (2 -3) the next are smooth, including subsequent 2-3 shifts from lights...until I switch off for more than 5 seconds.

I hear and read conflicting ideas, normal, not normal, etc. transmission has just been rebuilt to replace worn clutches, but not indication of this delayed shift was found.

How can one test the electrical delay? Where is it located?

Slow or delayed shift 2 to 3
 

My 1990 300SL does the same thing too...only difference is that it does it EVERY time I switch off the ignition for more than 5 seconds, whether the car is warm cold or just been driven for 2 hours.

It does this whether ambient temp is 90 in summer or 30 in winter...only that now in winter, it is even more exagerated, taking much longer to change first time.

Once it gets going after the first shift (2 -3) the next are smooth, including subsequent 2-3 shifts from lights...until I switch off for more than 5 seconds.

I hear and read conflicting ideas, normal, not normal, etc. transmission has just been rebuilt to replace worn clutches, but not indication of this delayed shift was found.

How can one test the electrical delay? Where is it located?

delayed gear change
 

Everyone seems to say that this is normal and "was designed" to work that way to quickly heat up the Cat. to "reduce exhaust emissions". Well this may be so, however, why is this oddity required when all other car manufacturers who also have Cats in their cars didn't have this "brilliant" invention and why wasn't it a "copy cat" item if it was such a brainwave from those designers??? Lets face it, even the latest new Mercs have got rid of this problem haven't they? An after thought perhaps?

Have to agree with Hocky -

It's funny that our '92 Q45 shifts as smooth as butter no matter what the engine temp.

The rough cold shifting is one thing I don't like about my '92 400e. I'd say our older MBZs are a bit "rough around the edges." This is behavior that I'd expect from a much lesser car.

What's the big deal? The car is designed to delay the 2-3 shift until the engine reaches a certain temperature in order to accelerate the warmup of the catalytic converter.

It usually affects only the first 2-3 shift after cold start.

So?

If this is all we have to worry about....

:rolleyes:

True that it is rationally, a functional behavior - but - for a car that is supposed to be "of the finest on the road" I find it a bit crude. Especially when other lesser/cheaper cars exhibit better behavoir in this area. I think cars that cost as much as these did at the time, have no excuse for bad behavior.

Hard shifting does not feel luxurious or well engineered.

Oh and we do have to worry about other things...

Like those pesky AC evaporators that cost over $2K to fix (mine's already leaking and I don't even have 60K on the clock)

For us M119-ers, wiring harnesses that get cooked and then fail ($1K to fix)