W211 722.6 lock up speed? experts only.

[V6Matty]

Gary, which specialist are you going to see in Bristol.

My Brother user these guys a couple of years ago for his Volvo, and he said they were excellent. Really knew their way around auto boxes.

http://www.icautomaticgearboxes.co.uk/

 

[AdamG]

I think Malcolm is right about lock up on most Mercedes' autos.

I believe the 722.6 and 722.9 do not lock up fully to smooth engine vibration. The later 722.9 7g plus does though.


http://api.viglink.com/api/click?fo...es-trani.PDF&jsonp=vglnk_jsonp_13512654982777


The above document talks of

"This damper design makes it possible to operate the torque converter lock-up clutch without slip – while ensuring maximum comfort with respect to the drive line noise caused by torsional excitation"

Back to the original question. I think Mercedes changed the lock up regime of the 722.6 gearbox to improve fuel consumption around 2001. This resulted in lock up at lower revs.

Cheers

Adam

 

[AdamG]

To add to my previous post.

There is a post on Benzworld discussing lockup variations:

http://www.benzworld.org/forums/w220-s-class/1561449-mercedes-s400-cdi-transmission.html

Also a link to a year 2000 mercedes info page:

http://web.archive.org/web/20000603093055/http://www.mercedes-benz.com/e/cars/s-class/facts_m4.htm

Adam

 

[television]

Can I shed a little light on the wording " the torque converter is never fully locked up" as put out be Mercedes and another link.

The torque converter will and does lock up at times, so you you can be cruising happily at 70 in top with the converter locked up, but it only stays locked up in certain conditions, the slightest throttle change, a slight incline, or decline and it is not locked up.

We know from the good links and not forums based links that there are differences in the different models as to when the converter locks up and the band that the lock up is working in.

The AMG have their own set of figures, so does the S class, so we know there are differences in the cars. We also know the the phase 2 722.9 boxes 2009 have another set of figures with tighter tolerances and lock up points.

Why anyone wants or thinks that the converter locks up on their car I will never know (unless you have a fault or incorrectly set up box).

The thing is it does lock up, but never completely, you cannot be driving along thinking that the box is locked up for without STAR on the front seat with live data you cannot tell, and this shows all of the qualities of a well designed box.

 

[spock500]

What's the history of the box?

Is it one of those 'sealed until it stops working boxes' or has it had an ATF change and filter?

 

[G-a-r-y]

Yes, filters and electro plate, but only 50k miles. From what I read it is designed to lock up. My problem is that it does it at 15mph in 1st gear. What senses throttle load and speed?

 

[television]

It is a combination of things, engine speed and road speed start the changing gear off,,,, when speed signal CAN info is lost, this could create an incorrect change, I take it they cleared the box ECU as the memory on these is very small

 

[G-a-r-y]

The more I drive the car the more I notice the fault, it's the jolt of lock-up in 1st gear @16mph FROM COLD.Once warmed up it's hardly noticeable.
After the electro plate was replaced last week it seems worse.
I've noticed from the invoice that they used Shell M-1375.4.
Taken from a wis document on the web it states only Shell ATF 3353 meets Mercedes 236.12 specification.
Could this wrong oil be making the lock-up more harsh and noticeable or should it not lock-up in 1st gear @ 16mph to start with?
Can someone with a W211 tell me how their car behaves?

 

[television]

Some how you are intent on believing that this is a lock up fault, other things can cause hard shifts, a sticking piston is one thing, again did they clear the fault codes

 

[Mr Teddy Bear]

My 208 only lock's up in 5th at steady engine/road speed combinations at moderately high road speed. There is no engine braking going down hill in top, the effect is of the vehicle running away and driving itself. Using the gear shift down to say third does produce engine braking. So at an educated guess I would bet that the torque converter is locked up then, because the design of the TQ redirect's the oil exiting the driven half, one of the inside bit via a stator back into the vanes of the driven part of the coupling. Theoretical principles suggest not a lot of engine braking with out locking up the TQ.

What does the OP mean by an electroplate?

When I had the oil and filter changed in my pre-2000 box I bought the the oil from the stealer, this came as a branded Merc item I believe is a full synthetic and cost an arm and a leg, bout 78 quid in 2007. The filter and sump pan joint were absolutely identical to those I sourced from Euro Car Parts. I compared like for like.

 

[G-a-r-y]

Some how you are intent on believing that this is a lock up fault, other things can cause hard shifts, a sticking piston is one thing, again did they clear the fault codes

My gear shifts are smooth, down shifts are smooth too. Under acceleration you can just about feel it unlock a tiny moment before it shifts down.

The gearbox people told me they cleared the codes. It's going back Monday PM and I will leave it there so they can drive it from cold. After reading all the stuff on the net I believe it's working correctly apart from this early harsh lock-up from cold.

It may be that this old box has been re-worked to make it a bit more economical using lock-up but in reality it needs more gears. Pitty I couldn't afford a car with 7G.

 

[G-a-r-y]

My 208 only lock's up in 5th at steady engine/road speed combinations at moderately high road speed. There is no engine braking going down hill in top, the effect is of the vehicle running away and driving itself. Using the gear shift down to say third does produce engine braking. So at an educated guess I would bet that the torque converter is locked up then, because the design of the TQ redirect's the oil exiting the driven half, one of the inside bit via a stator back into the vanes of the driven part of the coupling. Theoretical principles suggest not a lot of engine braking with out locking up the TQ.

What does the OP mean by an electroplate?

When I had the oil and filter changed in my pre-2000 box I bought the the oil from the stealer, this came as a branded Merc item I believe is a full synthetic and cost an arm and a leg, bout 78 quid in 2007. The filter and sump pan joint were absolutely identical to those I sourced from Euro Car Parts. I compared like for like.

I think the electro plate ( internal electrical controls of box) has a speed sensor which causes problems?

 

[television]

So much confusion about when a box is locked up, again most cannot tell it is is or not, why the concern over this feature, it locks up when it needs to and does not when not required to.

The speed plate cannot really cause this holding onto the gears, sure it locks up in 2nd when the speed signal is faulty, and this speed plate as it is called does no more than to operate the valves in the valve block that it is bolted to.

The ECU is programmed and it talks to the engine ECU to hold on to the first gears until the CAT has warmed up, on some cars this does appear to be excessive or over done.

Poor CAN communication missing or corrupted data, a sticking valve just so many things.